Is it possible to do work on an object that remains at rest? Work requires that a force acts over a distance. If an object does not move at all, there is no displacement, and therefore no work done.
Final answer:
Work in physics typically involves a force causing displacement, so no work is done on a resting object if there's no movement. However, internal work can be done on a deformable system that doesn't result in displacement, such as bending or compressing an object, which alters its internal energy.
Explanation:
In physics, the concept of work is defined as the process of transferring energy by the application of force along the direction of displacement of the object. According to this definition, if an object does not move, no work is done on it, even if a force is applied. This is because work is calculated by the equation W = F × d × cos(θ), where W is work, F is the force applied, d is the displacement, and θ is the angle between the force and the direction of displacement. Therefore, if d (displacement) is zero, the work done is also zero.
However, there are cases in deformable systems where net work can be done without causing a change in the mechanical kinetic energy. Such scenarios include the bending of a coat hanger or the compression of a gas where internal work is done on the system to alter its shape or volume rather than its movement, thus maintaining a state of rest even though internal energy may have changed.
In summary, if we're considering mechanical work related to movement against forces like gravity, and if the object remains at rest, then no work has been done on that object. However, it is important to note that work can be performed in other forms, such as internal work in a deformable system that does not result in a change in the object's position.
Which of the following shows a car that is increasing in speed
How much force is needed to accelerate a 1,800kg car at rate of 1.5 m/s2?
Given data:
acceleration (a) = 1.5 m/s² ,
mass (m) = 1800 Kg ,
Determine F = ?
From Newtons II law
F = m.a N
= 1800× 1.5
= 2700 N
2700 N force needed to accelerate the car
Answer: 2700 N force needed to accelerate the car
Explanation:
F = m.a N
= 1800× 1.5
= 2700 N
You hear the engine roaring on a race car at the starting line.Predict the changes in sound as the race starts and approaches the camera
A.the sound of the engine will get louder and pitch lower
B.the sound of the engine will get louder and pitch higher
C.the sound is determined by the car and it will not change in anyway
D.the sound of an engine will get louder but the pitch will not change
The answer is B because if you seen a movie you would see it happen
The change in the car engine's sound as it approaches the camera can be explained by the Doppler Effect. The sound will get louder, and the pitch will get higher.
Explanation:This question pertains to the Doppler effect observed in sound waves. When a race car starts its engines, the sound of the car's engine roaring is heard at a certain pitch. As the car begins to move towards you, the source of the sound gets closer and the waves reach your ear more frequently. This translates into our perception as a higher pitch. So, the correct answer is B. The sound of the engine will get louder and pitch higher as the car approaches the camera.
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a sphere with a mass of 12 g has a radius measuring 2 cm. what is its density
Formula for density is
D = mass/volume
So...
Answer: 0.3479 g/cm^3
hope this helps!
The density of the sphere is approximately 3.58×10⁶ g/m³ or 3.58g/cm³.
To calculate the density (ρ) of an object, you can use the formula:
ρ= 4/3 πr³
where m is the mass of the object and r is its radius.
In this case, the mass of the sphere is m=12g and the radius is r=2cm (r=0.02m in SI units).
Plugging in the values:
ρ= 12g / 4/3 π(0.02m)³
First, calculate the volume of the sphere:
Volume= 4/3 π(0.02m)³
Volume≈3.35×10⁻⁶ m³
Now, divide the mass by the volume to find the density:
ρ= 12g / 3.35×10⁻⁶m³
ρ≈3.58×10⁶ g/m³
Therefore, the density of the sphere is approximately 3.58×10⁶ g/m³ or 3.58g/cm³.
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The center on a high school basketball team wants to increase the maximum height of his jump. What statement correctly describes how he could achieve this goal?
Jumping with more acceleration
Answer:
Explanation:
D) Jumping with greater initial velocity would increase the height of his jump.
How does a mathematical model help you understand the science concepts? Give an example.
A mathematical model helps us understand science concepts by providing a simplified representation of complex phenomena.
Explanation:A mathematical model helps us understand science concepts by providing a simplified representation of complex phenomena. It allows us to analyze and predict the behavior of the real system without directly studying it. For example, the kinetic molecular theory of gases is a mathematical model that helps us understand the behavior of gases by describing them as collections of moving particles.
Plz help i need this is due in 45 mins ty
Figure 1
Speed is a scalar quantity, It has only magnitude but no direction. It is defined as rate of change of distance.
Mathematically, speed = distance÷time
S = d ÷ t
S = 2560 ÷ 60
S = 42.67 m/s.
Bits:
Speed is a scalar quantity, that describes only the magnitude (42.67 m/s) of the rate of change of an objects distance. Determine the objects speed requires a unit of distance per unit of time
Figure 2
Velocity is a vector quantity, It has both magnitude and direction. It is defined as rate of change of displacement.
Mathematically, Velocity = Displacement ÷ time
V = 75 ÷ 1.5
V = 50 Km/h.
Velocity is a Vector quantity that describes both the magnitude and direction of the rate of change of objects displacement plus it describes its position. An objects overall change in position is known as its Displacement per unit time.
An object with more mass has more kinetic energy than an object with less mass, if both objects are moving ____.
Select one:
a. in the same direction
b. in the opposite direction
c. at the same speed
An object with more mass has more kinetic energy than an object with less mass, if both objects are moving at the same speed. (c)
Answer:
c. at the same speed
Explanation:
alex goes shopping . he buys 2 hats that hat cost the same price and a scarfthat cost $17. total he spent $35. how much did each hat cost
35-17=18
18/2=9
9+9+17=35
Each hat cost him 9 dollars.
Which would BEST describes what occurs when a ball is thrown against a wall?
A) The ball will not bounce off the wall.
B) The ball hits the wall hard enough to bounce off of it.
C) The wall is stronger than the ball and neither exerts any forces.
D) The ball exerts a force on the wall and the wall exerts a force back.
When a ball is thrown against a wall, the ball exerts a force on the wall, and the wall exerts an equal force in the opposite direction back on the ball. (D)
Answer:
The ball exerts a force on the wall and the wall exerts a force back.
Explanation:
When a ball is thrown against a wall, the ball exerts a force on the wall and the wall exerts a force back. This is due to Newton's third law of motion. According to this law, every action have equal and opposite reaction and both action and reaction forces acts on different object.
In this case, when a ball is thrown against a wall, the wall exerts an equal force on the the ball but in opposite direction. It follows the newton's third law.
Hence, the correct option is (D).
1. A merging traffic sign is an example of a _____ sign.
A merging traffic sign is an example of a warning sign in traffic control. It warns that two separate streams of traffic will be converging into one lane, helping to manage traffic flow and prevent accidents.
Explanation:A merging traffic sign is an example of a warning sign. Warning signs are important in traffic control as they signal upcoming hazards so that drivers can prepare and react accordingly. In the case of a merging traffic sign, it indicates that two separate streams of traffic will be converging into one lane.
Understanding this sign is vital to maintain road safety. Think of it like when many vehicles speed through an intersection without regard to the posted speed limit. A traffic signal is installed to manage the flow of vehicles and prevent possible accidents. That's the same concept with a merging traffic sign – it signals drivers to prepare for incoming vehicles from another lane and take appropriate action to prevent collisions.
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Which describes a train’s acceleration if it changes speed from 25 m/s to 10 m/s in 240 s? positive acceleration no acceleration negative acceleration
To understand acceleration, you need to know speed and velocity.
Why?
Acceleration is the change in velocity, and the velocity equation is:
velocity = distance / time Units: (m/s)
If a change in position means an object has a velocity, then that means that a change in velocity has an acceleration (I recommend you look at the graphs, it will help a lot to understand the relationship between each).
Now that we have some background, lets use it to answer the problem!
The change in velocity is from 25 m/s to 10 m/s, and we have a time. Lets plug it into the (average) acceleration equation so we can visualize it better!
The symbol delta means "change" : Δ
a = Δv / Δt
expanded to:
a = vf - vi / tf - ti
(vf = velocity final, vi = velocity initial, tf = time final, ti = time initial)
So if the train's speed went from 25 m/s to 10 m/s, then that means that 10 m/s is our final velocity and 25 m/s is the initial:
a = 10 - 25 / 240
a = -15 / 240
a = -0.0625 m/s^2
Since we ended up with a negative number, it means that the train has a negative acceleration!!!!!
The fast way to do this:
25 m/s is bigger than 10 m/s, so that means that to go from 25 m/s to 10 m/s you have to slow down--otherwise known as putting on your brakes. So if the change in speed is negative then the acceleration will be negative.
In other words, if your final speed is less than your initial speed then your acceleration would be negative.
Sorry for the long explanation! I hope you never struggle with this again though!
Hope it helped,
Answer: negative acceleration
Explanation:
(50 POINTS) Set the ball and the barrier about two feet apart on the table. Grasp both ends of the ruler. Push the ball using the center of the ruler so the ball rolls, hits the barrier, and rebounds from it. Describe the motion of the ball as it moves.
Answer:
Kinetic energy
Explanation:
kinetic energy is the energy of motion. When something is moving it would be in motion so it would have kinetic energy.
Answer:
When an object, in your example, a ball, rolls (with rolling friction) bounces off of another surface, the force from the barrier is transferred into the ball causing it to roll back. (Newton’s third law)
Explanation:
how are the magnets able to have zero resistance
Magnets can have zero resistance due to the properties of superconductors. These materials exhibit zero electrical resistance and perfect diamagnetism at very low temperatures, a phenomenon known as the Meissner effect. Consequently, the magnetic field within a superconductor is zero, and once a current is established, it will persist without any applied voltage source.
Explanation:Magnets are capable of having zero resistance due to the properties of superconductors. Superconductors exhibit zero electrical resistance and perfect diamagnetism when cooled down to very low critical temperatures. This expulsion of all magnetic fields results in a net magnetic field of zero within the superconductor, even in the presence of an applied magnetic field, known as the Meissner effect.
An interesting consequence of this zero resistance is that once a current is established in a superconductor, it will persist without any applied voltage source. Furthermore, with a magnetic object, each surface you can imagine that encloses all or part of the magnet ultimately has zero net flux of magnetic field lines flowing through the surface. Just as many outward-flowing lines from the magnet's north pole pass through the surface as inward-flowing lines from the south pole of the magnet.
In superconductors, resistance disappearing is not the only intriguing phenomenon. The exclusion of magnetic fields, which is another manifestation of the Meissner effect, occurs as well. The forces on these currents tend to cancel, making the magnetic drag almost zero.
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Superconductivity, a state achieved at very low temperatures, allows magnets to have zero resistance and to expel all magnetic fields - a phenomenon known as the Meissner effect. In this state, a current persists without a needed voltage source. This property has practical applications such as in the technology used to levitate high-speed trains.
Explanation:In order for magnets to have zero resistance, they have to achieve a state known as superconductivity. Superconductivity is a phenomenon that occurs in some materials when they are cooled to very low critical temperatures. In this state, there is a resistance of exactly zero and all magnetic fields are expelled. This lack of resistance means that, once a current is established in a superconductor, it persists without an applied voltage source.
This is closely linked to something known as the Meissner effect, whereby superconductors expel all magnetic field lines. This perfect diamagnetism means that the net magnetic field within a superconductor is always zero — any magnetic field lines that pass through a superconducting sample when it is in its normal state are expelled once the sample becomes superconducting.
The practical applications of these properties are considerable. For instance, high-speed trains have been developed that levitate on strong superconducting magnets, exploiting the fact that a light, permanent magnet placed over a superconducting sample will levitate in a stable position above the superconductor.
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If a 1000 kg cannon at initialy at rest fires a 10 kg cannonball at 200 m/s, what is the final velocity of the cannon?
Since the whole cannon AND the lead cannonball inside it are starting out motionless, there's no momentum before the shot.
We know that momentum is conserved, so the total momentum after the shot must also be zero. This tells us that whatever momentum the ball carries away in THAT ===> direction, the cannon itself will have the same amount of momentum in THIS <=== direction. That way, they'll add up to zero like we need them to.
The physics we need: Momentum = (mass) x (velocity)
OK. All students hearing protection ready now. Ready on the left. Ready on the right. Ready on the firing line. Cannon discharge in three. Two. One. ZERO. BOOM !
-- 10 kg ball flying THAT way ==> at 200 m/s.
Momentum= (10kg)x(200 m/s THAT==>way = 2,000 kg-m/s THAT==>way
-- Cannon momentum = (1000 kg) x (velocity THIS <== way)
Cannon momentum = 2,000 kg-m/s THIS<==way
(1000 kg) x (velocity) = 2,000 kg-m/s this<==way
Divide each side by (1,000 kg):
Velocity = (2,000 kg-m/s) / (1,000 kg) this<==way
Velocity of the cannon = 2 m/s this<==way
If the bond enthalpy for a C-H bond is 413 kJ, what will happen when the C-H bond is broken?
Explanation:
Bond Enthalpy : It is defined as amount of energy required to break a the particular bond in there gaseous state. It is also known as bond energy. It units are kJ/mol.
Breaking of a bond is an Endothermic process (energy absorbed from the surroundings).Formation of bond is an Exothermic process (energy is released to the surroundings).If the average bond enthalpy for a C-H bond is 413 kJ/mol, When the C-H bond breaks in which energy will be required ,which will be an endothermic reaction.
Which energy transformation takes place when a firecracker explodes
Answer: Chemical energy to kinetic energy, heat energy, sound energy and light energy.
Explanation: The crackers are made up of gunpowder which is a chemical substance. When this gunpowder powder burns it produces smoke and hot gases (generation of heat and light energy) which create high pressure inside the can and blows the can open, and make all the tiny particles of powder blow out and chemical energy is converted to kinetic energy.
It makes the air to push outward and when it collapses back, it leads to generation of sound. So the chemical energy stored in gunpowder gets converted to sound.
If a rock is dropped with a weight of 50kg and friction due to air resistance produces a force of 98N, what is the net force in the Y direction?
PLEASE HELP 11 POINTS
Answer:
The net force is 392N, pointing down.
Explanation:
The net force is the sum of all forces acting on the rock, namely the gravity ("+" acting downward) and the friction force due to air resistance ("-" acting upward):
[tex]F_{net} = F_g - F_{air}\\F_{net} = m\cdot g - F_{air} = 50kg\cdot 9.8\frac{m}{s^2}-98N= (490-98)N=392N[/tex]
The net force is 392N and pointing down (positive)/
Which cools faster, land or water? Give a suitable reason for your answer.
Answer: Land cools faster than water
Reason: Water has high specific heat capacity, so it absorbs huge amount of heat energy to increase comparatively small amount of temperature. Loosing a large amount of heat requires more time, so water takes more time to cool down.
an 1150kg elevator moving down speeds up at a rate of 3.5m/s. what is the tension in the supporting cables?
Answer:
The tension force in the supporting cables is 7245N
Explanation:
There are two forces acting on the elevator: the force of gravity pointing down (+) with magnitude (elevator mass) x (gravitational acceleration), and the tension force of the cable pointing up (-) with an unknown magnitude F. The net force is the sum of these forces:
[tex]F_{net} = F_g - F = m\cdot g - F\\[/tex]
We are given the resulting acceleration along with the mass, i.e., we know the net force, allowing us to solve for F:
[tex]1150kg\cdot 3.5\frac{m}{s^2}= 1150kg \cdot 9.8\frac{m}{s^2}-F\\\implies F = 1150kg\cdot(9.8-3.5)\frac{m}{s^2}= 7245N[/tex]
The tension force F in the supporting cables is 7245N
Density (D) is defined by mass/volume . Which item decreases as heat is applied?
V
D
M
Answer;
density = (mass/volume)
here density varies with respect to change in volume by assuming constant volume.
changing the temperature, change in density. most matter increases in volume when it gets hotter. Example, when an iron rod is heated, it will get longer and its density will decrease. This happens because the mass of the rod constant, but volume increase.
If a gas has a gage pressure or 156 kPa, it’s absolute pressure is approximately
A. 56 kPa.
B. 100 kPa.
C. 256 kPa.
D. 300 kPa.
Answer: C
Gauge pressure = 156 kPa ,
What is absolute pressure =?
We know that,
absolute pressure = gauge pressure + atmospheric pressure
Pabs = Pgauge + Patm
= 156 + 101.3 (since atm.pr. = 101.3 Kpa)
= 257.3 KPa absoulte
approximately = 256 KPa absolue
The difference between an innate behavior and a learned behavior is that a learned behavior is __________ and an innate behavior is not.
A.
based on inborn responses
B.
instinctive
C.
based on reflexes
D.
a result of experience
Answer:
D. a result of experience
Explanation:
on edge
compare the mass of block A, the mass of block B is:
The mass of Block-B is DOUBLE the mass of Block-A. (choice-a)
The mass of Block-B is twice the mass of Block-A and the mass of products = mass of reactants. This question asks us about the law of conservation of mass. Thus, option A is correct.
What is law of Conservation of Mass?The law of conservation of mass states that matter can neither be created nor destroyed but can be transformed form one state or form to another. This is the basics of science which implies that whatever matter we have, it was created from something before it was converted into what we have at the moment.
However, this law does not hold nuclear reactions because they undergo changes in the core of the matter which can change the proton of that same matter or neutron from one element to another. This is to say that in nuclear reactions, matter can be created and it can also be destroyed.
Therefore, The answer to this problem is mass of products = mass of reactants and this question asks us about the law of conservation of mass. Thus, option A is correct.
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Which type of cloud is tall and associated with thunderstorms
Cumulonimbus clouds will be your answer. They are both tall and associated with thunderstorms. Hope I helped!
A spring, when compressed 0.20 m from the equilibrium position, stores 24 J. What is the value of the spring constant
Given that:
spring compressed ( x) = 0.2 m
Work (W) = 24 J
determine , spring constant (x)=?
We know hat ,
Work (W) = (1/2). k.x²
24 = 1/2 ( k × 0.2²)
48 = k × 0.2²
k = 1200 N/m
In a heat engine, if 700 j of heat enters the system, and the piston does 400 j of work, what is the final internal energy of the system if the initial energy is 1,200 j?
A 1,100 J
B 300 J
C 1,500 J
D 900 J
Given that
Heat (Q) = 700 J ,
Work (W) = 400 J ,
What is the final internal energy of the system (u₂) = ?
given (u₁) = 1200 J
we know that ΔU = Q - W Joules,
(U₂ - 1100) = 700 - 400
U₂ = 300 +1100
= 1400 J
The final internal energy is 1400 J
in a transfer of energy, there is no change in the energy's, what?
I think it is there is no change in the energy's sunlight
A car travels at 84 kilometers per hour for 7 hours. How far did it travel?
In optics, a diffraction ___________ is an optical component with a periodic structure, which splits and diffracts light into several beams traveling in different directions
Answer:
grating
Explanation:
Diffraction is a phenomenon in which light bends at the edges of an object because of which light falls even in the shadow region.
Diffraction grating consists of thousands of slits through which the light splits. The diffracted light travels in different directions and forms a alternate dark and bright fringes.