the question is correct
James threw a ball vertically upward with a velocity of 41.67ms-1 and after 2 second David threw a ball vertically upward with a velocity of 55.56ms-1.When the balls will be at the same height?
Answer:
When have passed 3.9[s], since James threw the ball.
Explanation:
First, we analyze the ball thrown by James and we will find the final height and velocity by the time two seconds have passed.
We'll use the kinematics equations to find these two unknowns.
[tex]y=y_{0} +v_{0} *t+\frac{1}{2} *g*t^{2} \\where:\\y= elevation [m]\\y_{0}=initial height [m]\\v_{0}= initial velocity [m/s] =41.67[m/s]\\t = time passed [s]\\g= gravity [m/s^2]=9.81[m/s^2]\\Now replacing:\\y=0+41.67 *(2)-\frac{1}{2} *(9.81)*(2)^{2} \\\\y=63.72[m]\\[/tex]
Note: The sign for the gravity is minus because it is acting against the movement.
Now we can find the velocity after 2 seconds.
[tex]v_{f} =v_{o} +g*t\\replacing:\\v_{f} =41.67-(9.81)*(2)\\\\v_{f}=22.05[m/s][/tex]
Note: The sign for the gravity is minus because it is acting against the movement.
Now we can take these values calculated as initial values, taking into account that two seconds have already passed. In this way, we can find the time, through the equations of kinematics.
[tex]y=y_{o} +v_{o} *t-\frac{1}{2} *g*t^{2} \\y=63.72 +22.05 *t-\frac{1}{2} *(9.81)*t^{2} \\\\y=63.72 +22.05 *t-4.905*t^{2} \\[/tex]
As we can see the equation is based on Time (t).
Now we can establish with the conditions of the ball launched by David a new equation for y (elevation) in function of t, then we match these equations and find time t
[tex]y=y_{o} +v_{o} *t+\frac{1}{2} *g*t^{2} \\where:\\v_{o} =55.56[m/s] = initial velocity\\y_{o} =0[m]\\now replacing\\63.72 +22.05 *t-(4.905)*t^{2} =0 +55.56 *t-(4.905)*t^{2} \\63.72 +22.05 *t =0 +55.56 *t\\63.72 = 33.51*t\\t=1.9[s][/tex]
Then the time when both balls are going to be the same height will be when 2 [s] plus 1.9 [s] have passed after David throws the ball.
Time = 2 + 1.9 = 3.9[s]
Helppp me please !!
Answer:
the frequency of this light is [tex]1.5\,\,10^{16}[/tex] Hz (which coincides with the fourth option listed among possible answers)
Explanation:
Recall the relationship between wavelength and frequency of radiation based upon the speed of light in vacuum:
[tex]frequency\,*\,wavelength\,=\, speed\,\,of\,light\\frequency\,*\,wavelength\,=\,3\,\,10^8\,\frac{m}{s} \\frequency\,*\,20 \,\,10^{-9}\,m\,=\,3\,\,10^8\,\frac{m}{s}\\frequency\, =\,\frac{3\,\,10^8}{2\,\,10^{-9}} \,\frac{1}{s} \\frequency\,=1.5\,\,10^{16}\,\,Hz[/tex]
In the process shown above, we have written the speed of light in meters per second, and also converted the 20 nano-meters into meters, in order to reduce SI units properly and have the result shown in units of 1/second (that is hertz's - abbreviate "Hz")
Letti is having a problem in her experiment that she does not know how to solve. In order to move forward, Letti needs to be .
Answer:
In order to move forward, Letti needs to be creative.
Explanation:
Creative:
A person is said to be creative if that person has ability to think out of the box.
For example: if a person having a problem and instead of using traditional methods of solving the problem then that person thinks about news ideas then that person is creative,
As in our case, letti can use problem solving technique to find a solution of her problem.
Creative Problem technique:
It is such a problem solving method in which we use unconventional ways to get the solution of a problem. We analyze the problems with news view points so that we can reach at innovative ideas of solutions.
Answer: creative
Explanation: i just took the test
In what way is a projectile (a ball thrown horizontally for example) using constant velocity motion?
Can someone please answer this?
Pleaseeeee❗️❗️❗️❗️
Answer:
The horizontal component of the velocity is always constant in accordance with the Newton's first law of motion since there is no other force acting in the horizontal direction.
Explanation:
A ball moving in projectile motion is under a variable resultant velocity on the object but the horizontal component of the velocity is always constant in accordance with the Newton's first law of motion since there is no other force acting in the horizontal direction. While a projectile motion the body is always under the influence of gravity and so its vertical component of velocity varies continuously. During the analysis of such a problem we always break the velocity components of the body for our ease of evaluation using the equations of motion.A rubbit gets down from a rump which its /\x=0.85m in 0.5s, The rubbit's mass is 2kg, what is the net Force?
Answer: 13.6 N
Explanation:
The equation of motion for the rabbit is:
[tex]\Delta x=V_{ox}t+\frac{1}{2}a_{x}t^{2}[/tex] (1)
Where:
[tex]\Delta x=0.85 m[/tex] is the distance traveled by the rabbit
[tex]V_{ox}=0 m/s[/tex] is the rabbit's initial velocity, assuming it started from rest
[tex]t=0.5 s[/tex] is the time
[tex]a_{x}[/tex] is the acceleration
Isolating [tex]a_{x}[/tex]:
[tex]a_{x}=\frac{2 \Delta x}{t^{2}}[/tex] (2)
[tex]a_{x}=\frac{2 (0.85 m)}{(0.5)^{2}}[/tex] (3)
[tex]a_{x}=6.8 m/s^{2}[/tex] (4)
On the other hand, the force [tex]F_{x}[/tex] is given by:
[tex]F_{x}=m.a_{x}[/tex] (5)
Where [tex]m=2 kg[/tex] is the mass of the rabbit
Substituting (4) in (5):
[tex]F_{x}=(2 kg)(6.8 m/s^{2})[/tex] (6)
Finally:
[tex]F_{x}=13.6 N[/tex]
EL. A white ball with mass 143 g is moving at a velocity of 7.9 m/s.
CS
It collides with a red ball with mass of 150 g.
The red ball is stationary before the collision. The white ball stops after the collision.
Calculate the velocity of the red ball after the collision.
Give your answer to two significant figures.
Answer:
[tex]\displaystyle v_2'=7.5\ m/s[/tex]
Explanation:
Conservation Of Linear Momentum
The total momentum of both balls won't change regardless of their interaction while no external forces are acting on the system. We'll use the following variables m1,m2,v1,v2,v1',v2' for the mass of the white ball, the mass of the red ball, their velocities before the collision, and their velocities after the collision, respectively .
The provided data is as follows:
[tex]\displaystyle m_1=143\ gr=0.143\ kg[/tex]
[tex]\displaystyle v_1=7.9\ m/s[/tex]
[tex]\displaystyle m_2=150\ gr=0.15\ kg[/tex]
[tex]\displaystyle v_2=0[/tex]
[tex]\displaystyle v_1'=0[/tex]
To preserve the total linear momentum, the following equation must stand
[tex]\displaystyle m_1\ v_1+m_2\ v_2=m_1\ v_1'+m_2\ v_2'[/tex]
Solving for [tex]v_2'[/tex]
[tex]\displaystyle v_2'=\frac{m_1\ v_1+m_2\ v_2-m_1\ v_1'}{m_2}[/tex]
[tex]\displaystyle v_2'=\frac{0.143(7.9)+0-0}{0.15}[/tex]
The final speed of the red ball is
[tex]\boxed{\displaystyle v_2'=7.5\ m/s}[/tex]
Final answer:
The final velocity of the red ball after the collision, calculated using conservation of momentum, is approximately 1.13 m/s to two significant figures.
Explanation:
Using the principles of conservation of momentum, we can solve for the final velocity of the red ball after the collision. The formula for conservation of linear momentum in a two-object system is m1v1 + m2v2 = m1v1' + m2v2', where m represents mass, v represents initial velocity, and v' represents final velocity. Since the white ball (m1 = 143 g) stops after the collision, its final velocity is 0 m/s. The red ball (m2 = 150 g) is initially stationary, so v2 = 0 m/s. From the data given, we can set up the equation as follows:
143 g × 7.9 m/s + 150 g × 0 m/s = 143 g × 0 m/s + 150 g × v2'
Solving for v2' (the final velocity of the red ball), we get v2' = (143 g × 7.9 m/s) / 150 g. Converting grams to kilograms to use SI units, we calculate:
v2' = (0.143 kg × 7.9 m/s) / 0.150 kg
v2' = 1.13 m/s.
The velocity of the red ball after the collision is approximately 1.13 m/s to two significant figures.
A snowboard has a mass of 1.53 kg. What is the static frictional force on the snowboard if the
waxed snowboard was lying horizontally on a wet & snowy surface (u s = 0.2)?
Answer:
Static friction, F=2.9988 N
Explanation:
Static Friction: It is the friction between two or more solid body that are not moving relative to each other.
When an external force is applied to a body that is in contact with another body, static friction opposes the applied force upto a certain limit, keeping the body at rest. When the applied force exceeds the certain limit the body begins to move. At that moment applied force is equal to limiting value of static friction F.
It varies linearly with normal force(N)
F∝N
F=μN (where μ is constant of proportionality and known as coefficient of static friction)
Now,
Mass, m=1.53 kg
Coefficient of static friction, μ=0.2
Normal force, N=m×g
=[tex]1.53\times9.8[/tex] (g=9.8 m/s²)
=14.994 N
Static friction, F= μN
=[tex]0.2\times14.994[/tex]
= 2.9988 N
Which statements describe both male and female reproductive systems? Check all that apply. A:The reproductive system produces hormones. B:The reproductive system transports reproductive cells. C:The reproductive system produces reproductive cells. D:The reproductive system includes the urinary bladder. E:The reproductive system develops and nourishes a developing baby.
Answer: A:The reproductive system produces hormones.
B:The reproductive system transports reproductive cells.
C:The reproductive system produces reproductive cells.
Explanation:
A:The reproductive system produces hormones. : The reproductive organs ovaries in females and testes in males produces hormones. The ovaries produce estrogen and progesterone and testes produce testosterone.
B:The reproductive system transports reproductive cells. : The ovaries in females transfers an egg into the fallopian tube and testes in males secrete sperms at the time of copulation the fertilization of egg and sperm leads to the development of zygote the precursor of new life.
C:The reproductive system produces reproductive cells.: The ovaries undergo oogenesis and in testes spermatogenesis takes place to develop egg and sperms respectively.
The statements describing the reproductive system are production of hormones and gamete along with the transport. Thus, statements A, B and C are correct.
The reproductive system has been the organ system in the human body that has been function for the reproduction of the organism.
Functions of Reproductive systemThe reproductive system in males has been comprised of testes that produces the male hormones' testosterone. The female reproductive system has been comprised of the ovaries that has been producing estrogen and progesterone.
The male and female reproductive system are responsible for producing male and female gamete and transport them for reproduction.
Thus, the statements describing the reproductive system are production of hormones and gamete along with the transport. Thus, statements A, B and C are correct.
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Analyze the following terms and phrases about solar activity. Select the two that represent correct matches between cause and effect.(1 point)
a) solar activity -- sudden eruptions of large bubbles of plasma and magnetic energy
b) coronal mass ejection -- relatively cool spot on surface of the sun
c) sun's magnetic field -- uneven churning of the sun's gravitational field
d) solar flare -- sudden release of magnetic energy
e) sunspot -- magnetic field of the sun emerges as a loop
Answer:
a) solar activity -- sudden eruptions of large bubbles of plasma and magnetic energy
and
d) solar flare -- sudden release of magnetic energy
Explanation:
We can start by eliminating the options that are definitely wrong.
A coronal mass ejection is not a relatively cool spot on surface of the sun, in fact such a spot is a sunspot, while a coronal mass ejection occurs when the magnetic field of the sun emerges as a loop. Thus, both options B and E are incorrect, leaving only A, C, and D. Option C makes no sense, as the sun's gravitational field does not 'churn'. Thus, only options A and D are left. A closer look at A and D reveals they are correct; solar flares are in fact sudden releases of magnetic energy, as seen in this quote from UC Berkeley's website; "Solar flares are caused by sudden changes of strong magnetic fields in the Sun's corona.". And solar activity is a blanket term for the effects of eruptions of plasma and magnetic energy from the sun.
Which statements accurately differentiate between dark matter and dark energy? Select the two correct answers.
a)Dark energy is the cause of the acceleration of the universe, while dark matter is the cause of the formation of structures.
b) There is much more dark matter in the universe, by mass.
c) Dark matter is the cause of the acceleration of the universe, while dark energy is the cause of the formation of structures.
d) Dark matter is black, while dark energy cannot be seen.
e) There is much more dark energy in the universe, by mass.
Answer:
a) Dark energy is the cause of the acceleration of the universe, while dark matter is the cause of the formation of structures.
e) There is much more dark energy in the universe, by mass.
Explanation:
Dark energy rises as an explanation of the accelerated expansion of the Universe, since it was expected that this slow down since The Big Bang, as a consequence of the gravitational attraction between the different objects (galaxies, planets, etc) but instead, the observations show how it is accelerating.
Dark matter in the other hand was born to explain why stars that were more farther for the supermassive black hole in the center of the Milky way galaxy didn't decrease their rotational velocity as it was expected.
[tex]v = \sqrt{\frac{G M}{r}}[/tex]
Where v is the rotational velocity, G is the gravitational constant, M is the mass inside the orbital radius, and r is the orbital radius.
If the distance increases the orbital speed decreases (inversely proportional).
Answer:a and e
Explanation:
Different color ca
ferent color candy canes are tested to see
one type dissolves faster. What is the
independent variable?
Answer: The color of candy cane
Explanation:
An independent variable is the Variable that the scientist changed in order to change the dependent variable. The scientist changes the color of the candy cane to test the rate at which they dissolve.
Final answer:
The independent variable in this experiment is the color of the candy canes, while the dependent variable is the rate of dissolution. The student is testing different colors to see if they affect the dissolution rate.
Explanation:
The independent variable in this experiment is the different color of candy canes. The dependent variable is the rate at which each type of candy cane dissolves. By testing different colored candy canes, the student is investigating if there is a difference in the dissolution rate based on color.
13. Bari kicked a ball and its leaves the ground at an angle 30° with a velocity of 20 m/s.
Find hang time of the ball
11 Pari Iricked a ball and its leaves the ground at an angle 30° with a velocity of 20. m/s.
I have a physics test upcoming and I’m particularly stuck on this question and I would be grateful if anyone could help me out.
Answer:
The hang time is 2.04 seconds
Explanation:
2-D Motion
It referred to as a situation where an object is launched in such a way it describes a curve, reaches a top height and then returns to ground level after traveling a certain distance x away from the launch point.
Let [tex]v_o[/tex] be the launching speed forming an angle [tex]\theta[/tex] with the horizontal reference. The hang time (time the object remains in the air) is given by
[tex]\displaystyle t_h=\frac{2V_{oy}}{g}[/tex]
Since
[tex]\displaystyle v_{oy}=v_o\ sin\theta[/tex]
Then
[tex]\displaystyle t_h=\frac{2v_o\ sin\theta }{g}[/tex]
We'll use the given values
[tex]\displaystyle v_o=20\ m/s\ ,\ \theta =30^o[/tex]
[tex]\displaystyle t_h=\frac{2(20)sin30^o}{9,8}[/tex]
[tex]\displaystyle t_h=2.04\ sec[/tex]
The hang time is 2.04 seconds
What are the top three osha cited ladder violations
Answer: not having a portable ladder extend 3 feet above the landing
improper use of the top of step ladders
lack of work or training
Explanation: career safe online
The top three OSHA cited ladder violations are improper maintenance, improper use, and missing fall protection systems, endangering worker safety.
These violations are common because they relate to fundamental ladder safety. Maintaining a ladder's condition is crucial to ensure it's safe for use. Inadequate ladder use includes actions that increase the risk of falls, such as reaching too far or using a ladder not designed for the task.
Missing fall protection is a serious violation, especially when working at heights where a fall could lead to severe injuries or fatalities. Employers must ensure proper ladder training, maintenance, and use, and provide the necessary safety equipment to protect workers from fall hazards. Violations in these areas can result in OSHA citations and penalties.
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a 40.0 kilogram child exerts a 100 newton force on a 50.0 kilogram object the magnitude of the force that the object exerts on the child is?
A) 0.0N
B) 80.0N
C) 100N
D) 125N
Answer:
The answer is choice C.
Explanation:
According to Newtons third law of motion, the force that object exerts on the child is equal and opposite to the force that the child exerts on the object:
[tex]F_{child}=-F_{object}[/tex]
Thus if the child exerts a force of 100 newtons on the object, the object must also exert a force of 100 newtons on the child but in the opposite direction.
The magnitude of the force the object exerts on the child is 100 N.
The given parameters;
mass of the child, m = 40 kgforce exerted by the child, F = 100 Nmass of the object = 50 kgAccording to Newton's third law of motion, for every action there is an equal and opposite reaction.
The magnitude of the force the child exerted on the object is equal to the force the object exerted on the child.The direction of these forces are opposite.Thus, the magnitude of the force the object exerts on the child is 100 N.
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What is the kinetic energy of a 50-kg child running to catch the school bus at
2 m/s?
O A. J
O B. 25 J
O C. 100J
O D. 200
Answer:
Option C
100 J
Explanation:
Kinetic energy, KE is given by
[tex]KE=0.5mv^{2}[/tex] where m is the mass and v is the velocity
Substituting 50 Kg for mass, m and 2 m/s for velocity v then we obtain
[tex]KE=0.5*50*2^{2}=100 J[/tex]
Therefore, the child's kinetic energy is equivalent to 100 J
Answer:100J
Explanation:
The infection where the air sacs in the lungs fill up with fluids is called:
A.
Pneumonia
B.
COPD
C.
Sleep apnea
D.
None of the above
Answer:
A
Explanation:
Pneumonia
1. An object is moving in a straight line at constant speed. Which of the following is true?
There are no forces acting on the object.
The object has 0 acceleration.
The object has constant velocity.
a. I only
b. ll only
c. II and III only
d. I, II, and III
c. II and III only (the object has 0 acceleration and the object has constant velocity.)
Why?
Let's discard each of the given options to find the correct one(s).
- There are no forces acting on the object:False, if an object has a constant speed, it does not mean that there are no forces acting on it, in fact, there will be always acting forces, like frictional force, gravity force, air resistance, and others.
- The object has a 0 acceleration:True, in an object is moving at constant speed, it means that there is no acceleration, the speed will be the same all the time during motion.
- The object has constant velocity:True, if an object is moving in a straight line at constant speed the velocity will be also constant. The velocity of an object is referring to its speed and its direction, if the object is moving in a straight line, the direction will be the same, so, if the speed is constant, the velocity will be also constant.
Have a nice day!
Saul is in Germany, driving on the
Autobahn. He drives 50 km in fifteen
minutes. How fast is Saul driving?
a. 50 km/h
b. 100 km/h
c. 200 km/h
d. 400 km/h
Answer: c
Explanation:Use equation for speed: V=S/t
S=50 km -distance
t=15 min=0.25h -time
V=?
------------------------
V=S/t
V=50km/0.25h
V=200km/h
A 10kg rocket is traveling at 80 m/s when the booster engine applies a constant forward force of 60 N for 3.0 seconds. What impulse
does the booster engine supply? What is the resulting velocity of the rocket?
Answer:
Impulse = 90
Resulting Velocity = 89
Explanation:
Use F * change in time = m * change in velocity.
For the first part of the question, the left side of the equation is the impulse. Plug it in.
60 * (3.0 - 0) = 90.
For the second half. we use all parts of the equation. I'm gonna use vf for the final velocity.
60 * (3.0 - 0) = 10 * (vf - 80). Simplify.
90 = 10vf - 800. Simplify again.
890 = 10vf. Divide to simplify and get the answer.
The resulting velocity is 89.
The impulse supplied by the booster engine is 180 Ns and the resulting velocity of the 10kg rocket is 98 m/s.
The question involves calculating the impulse delivered by the booster engine of a rocket and its resulting velocity. The impulse is obtained through the relationship Impulse = Force × Time. By applying a constant forward force of 60 N for 3.0 seconds, the impulse can be calculated as:
Impulse = 60 N × 3.0 s = 180 Ns (Newton-seconds)
To find the resulting velocity of the rocket, we use the impulse-momentum theorem which states that the impulse applied to an object is equal to the change in momentum of the object. Since the rocket's mass is constant, the change in momentum can also be expressed as the mass of the rocket times the change in velocity (Impulse = Change in momentum = Mass × Change in velocity). Therefore:
Change in velocity = Impulse / Mass
Change in velocity = 180 Ns / 10 kg = 18 m/s
The initial velocity of the rocket is 80 m/s, so the final velocity of the rocket after the impulse will be:
Final velocity = Initial velocity + Change in velocity = 80 m/s + 18 m/s = 98 m/s
what is the displacement for a person that walks 3.0km north and 8.0 km south
Answer:
5 km
Explanation:
x = |3 - 8| = 5 km
Help Meeeeee
Two kids are roller skating. Amy, with a mass of 55 kg, is traveling forward at 3 m/s. Jenny, who has a mass of 40 kg, is traveling in the opposite direction at 5 m/s. They crash into each other and hold onto each other so that they move as one mass. How fast are they traveling?
Answer:
0.4 m/s
Explanation:
From the law of conservation of momentum, the sum of initial momentum equals the sum of final momentum
Momentum, p=mv where m is the mass and v is the velocity
[tex]m_1v_1+m_2v_2=(m_1+m_2)v_c[/tex] where [tex]v_c[/tex] is the common velocity, [tex]v_1[/tex] and [tex]v_2[/tex] are velocities of Amy and Jenny respectively, [tex]m_1[/tex] and [tex]m_2[/tex] are masses of Amy and Jenny respectively.
Taking forward direction as positive, opposite direction is negative hence [tex]v_1[/tex] is 3 m/s while [tex]v_2=-5 m/s[/tex]
[tex]55 kg\times 3 m/s +(40 kg\times -5 m/s)=(55 kg+40 kg)v_c[/tex]
[tex]95 kg v_c=-35 kg.m/s[/tex]
[tex]v_c=\frac {-35}{95}=-0.368421053 m/s\approx -0.4 m/s[/tex]
Therefore, they travel at 0.4 m/s in the direction of Jenny's movement
What type of power plant burns material to make electricity?
Answer:
A fossil fuel power station is a thermal power station which burns a fossil fuel, such as coal or natural gas, to produce electricity. Fossil fuel power stations have machinery to convert the heat energy of combustion into mechanical energy, which then operates an electrical generator.
Explanation:
A wave with a period of three seconds travels at a speed of 12 m/s what is the wavelength of the wave
Answer:
λ = 0.28m
Explanation:
Equation used is v = λf, where v is velocity, λ is wavelength, and f is frequency
We need to find wavelength so rearrange the equation in term of wavelength.
v = λf
λ = f/v
We know that period is the inverse of frequency (f = 1/T), so lets substitute that into our equation
λ = f/v
λ = (1/T)/v
Plug in your the given values given in the question.
We're given v=12m/s and T=3sec
λ = (1/T)/v
λ = (1/3)/12
λ = 1/36 = 0.2777777 = 0.28m
Final answer:
The wavelength of a wave with a 3-second period traveling at 12 m/s is 36 meters.
Explanation:
To find the wavelength of a wave, you can use the formula:
wavelength = wave speed x period. In this case, the period of the wave (T) is 3 seconds and the wave speed (v) is 12 m/s.
wavelength = 12 m/s x 3 s = 36 meters.
Therefore, the wavelength of the wave is 36 meters.
Can somebody match the following please I need to pass this class
Answer:
Explanation:
B)2) Statosphere
E) 5) Exosphere
A) 1) Troposphere
C)3) Mesosphere
D) 4) Thermosphere
determine the proper unit for momentum using dimensionsal analysis
The unit for momentum is [tex]kg ms^{-1}[/tex]
Explanation:
The momentum of an object is defined as the product between the mass of the object and its velocity:
[tex]p=mv[/tex]
where
m is the mass of the object
v is its velocity
Let's determine the units for the momentum starting from the mass and the velocity:
The mass has units of kilograms, [tex]kg[/tex]The velocity has units of metres per second, [tex]ms^{-1}[/tex]Therefore, the unit for momentum is
[tex][p] = [m][v] = (kg)(ms^{-1}) = kg ms^{-1}[/tex]
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Final answer:
The proper unit for momentum, determined using dimensional analysis, is kilogram meters per second (kg·m/s), which is derived from the product of mass (in kilograms) and velocity (in meters per second).
Explanation:
To determine the proper unit for momentum using dimensional analysis, we first need to understand the physical definition of momentum. Momentum (π) is the product of an object's mass (m) and its velocity (v), thus having the formula π = m × v. According to SI units, mass is measured in kilograms (kg) and velocity in meters per second (m/s).
Performing dimensional analysis, we get:
Mass (m): [M] – SI unit: kg
Velocity (v): [LT−1] – SI Unit: m/s
Therefore, the dimensions of momentum are [M][LT−1] = [MLT−1]. When we multiply the units of mass and velocity, we get the unit of momentum as kilogram meters per second (kg·m/s), which is the proper unit for momentum.
a 75 kilogram boy initally at rest skis down the slope as shown assuming no frictional loss what will be his kinetic energy at the bottom of the slope
Answer:
The kinetic energy at bottom, K.E = 73500 J
Explanation:
Given data,
The mass of the boy, m = 75 kg
Let the height of the hill be, h = 100 m
The P.E is maximum at the top of the hill. Since the boy is at rest at the top of the hill, his K.E is zero.
When he reaches the bottom, his K.E is maximum and P.E is zero.
According to the law of conservation of energy, K.E at the bottom is equal to the P.E at top.
P.E = mgh
= 75 x 9.8 x 100
= 73500 J
Hence, the kinetic energy at bottom, K.E = 73500 J
An object with a mass of 20 kg has a net force of 80 N acting on it. What is the acceleration of the object?
Answer:
4 m/s²
Explanation:
The formula used here:
F = ma
F is force (80 N)
m is mass (20 kg)
a is acceleration
Since we need to calculate acceleration we will arrange the formula:
a = F ÷ m
Now substitute the values and solve
a = 80 ÷ 20
a = 4
The proper unit for this acceleration is m/s²
So the object accelerates at 4 m/s²
Answer:
4 m/s^2
Explanation:
F = ma
80N = (20kg)a
80N/(20kg) = (20kg)a/(20kg)
4 m/s^2 = a
Sonja is riding her bike. She takes her feet
off the pedals to freewheel down a hill.
Describe the energy transfers that take place as the bike travels down the hill.
Ignore friction and air resistance.
Answer:gravity
Explanation:
As Sonja coasts down the hill on her bike, the gravitational potential energy is converted into kinetic energy, which is the energy that increases her speed as she moves downhill.
When Sonja freewheels down the hill on her bike, the primary energy transfer is the conversion of gravitational potential energy to kinetic energy. At the top of the hill, the bike has a certain amount of potential energy due to its elevated position. As she moves downhill, this potential energy is converted into kinetic energy, which is the energy of motion, allowing the bike to increase in speed.
If we were not to ignore friction and air resistance, these factors would cause some of the kinetic energy to transform into thermal energy, due to the friction between the bike tires and the road as well as the air resistance against the rider and the bike.
However, since the question asks us to ignore these factors, we focus solely on the transformation of gravitational potential energy into kinetic energy as Sonja coasts down the hill.
You push a book sitting on a desk with a force of 5 N, but the book does not move. What is the static friction?
Answer:
The static friction is 5 N acting in the direction opposite to that of the force of push.
Explanation:
Given:
A book lying on a table. Force of push is 5N.
Now, the book is not moving. This clearly means that some resistive force is acting in the opposite direction which has the same magnitude as that of the applied force, thus making the net force acting on the book equal to zero.
This resistive force acting in the opposite direction is called the static frictional force.
Therefore, the static friction acting on the book is equal to 5 N and acts in the direction opposite to that of the force of push.
Which of the following is the dot product of u = 4i + 6j – 5k and v=-10i – 8j + 10k?
Answer:
[tex]\vec u\ . \ \vec v=-138[/tex]
Explanation:
Dot Product of Vectors
The dot product of two vectors is also known as scalar product. Given the vectors
[tex]\vec u=4\hat i+6\hat j-5\hat k[/tex]
[tex]\vec v=-10\hat i-8\hat j+10\hat k[/tex]
The dot product is the sum of the products of each component separately
[tex]\vec u\ . \ \vec v=(4)(-10)+(6)(-8)+(-5)(10)[/tex]
[tex]\vec u\ . \ \vec v=-40-48-50=-138[/tex]