Answer:
Option A and Option D are correct.
Explanation:
We have the Newton's second law, that is rate of change of momentum is force.
[tex]\frac{dP}{dt}=F\\\\\frac{mv-mu}{dt}=F[/tex]
So if there is a force mv - mu ≠ 0
v - u ≠ 0
v ≠ u
Final velocity ≠ Initial velocity.
a) Option A is correct since there is a force
b) Option B is wrong since total force is zero.
c) Option C is wrong since total force is zero.
d) Option D is correct since there is an effective force
Option A and Option D are correct.
Which of the following is true about the solar system?
A.
Most of the planets have moons.
B.
Earth is the only planet that has a moon.
C.
None of the planets have moons.
D.
All of the planets have moons.
A star is born when gas and dust from a nebula become so dense and hot that nuclear fusion starts. Which of the following forces is responsible for the formation of a star?
A.
friction
B.
gravitation
C.
magnetism
D.
electromagnetic energy
Answer: B. gravitation
Explanation:
Nebula is a stellar nursery. It is composed of dust and gases. This molecular cloud condenses under its own weight and forms a core which spins and gathers more mass due to gravity. This causes temperature and pressure to rise which kicks in the nuclear fusion reaction and a star is said to be born.
Thus, gravitation is responsible for formation of star.
The electrons that produce the picture in a
TV set are accelerated by a very large electric
force as they pass through a small region in
the neck of the picture tube. This region is
1.6 cm in length, and the electrons enter with
a speed of 1 × 10^5 m/s and leave with a speed
of 2.5 × 10^6 m/s.
What is their acceleration over this 1.6 cm
length?
Answer in units of m/s^2
.
Can protons be gained or lost in an element?
Which sphere forms Earth's outermost layer?
Atmosphere
Biosphere
Cryosphere
Hydrosphere
Answer:
The Atmosphere
Explanation:
Why is it that auroral displays above Colorado can be forecast several days in advance?
Use the diagram to answer the question.
Number of Chirps per Minute
Cricket 15 ° C 20 ° C 25 ° C
1 91 135 180
2 80 124 169
3 89 130 176
4 78 125 158
5 77 121 157
Average 83 127 168
Which statement indicates a reasonable conclusion based on the data from this experiment?
Decreasing the number of chirps causes the temperature to drop.
Cricket chirping increases with an increase in temperature.
Decreasing the temperature increases the number of chirps.
Temperature can be increased by increasing the number of chirps.
Answer: Cricket chirping increases with an increase in temperature.
Explanation:
The independent variable in the experiment is the variable which can be altered, manipulated and changed so as to determine it's influence over the dependent variable, which is the outcome of the experiment.
Here in the given experiment, the number of chirps is the dependent variable which is increasing due to the increase in the temperature which is the independent variable.
As you know, the oceans are a complex system that covers most of the earth, and contains a huge amount of resources. Protecting these resources is one reason to try and prevent the pollution of the oceans.
Algae is one ocean resource in particular that is vulnerable to pollution. The algae are a valuable resource because they absorb carbon dioxide from the atmosphere and release ____________ into the atmosphere.
A) oxygen
B) nitrogen
C) water vapor
D) carbon monoxide
Algae are green in color because they have chlorophyll. It captures sunlight and Carbon dioxide from the atmosphere and undergoes chemical reaction to produce food and Oxygen as a product. Since, there is no way to store the Oxygen gas in the algae, it releases the Oxygen to the ocean and atmosphere. This oxygen is used by all the aquatic and land animals which live on earth.
What does the phrase rise over run refer to when defining slope
What is the relationship between height and gpe
The relationship between height and gravitational potential energy is directly proportional, following the equation G.P.E. = mgh. GPE increases as the height of an object increases, and it is measured in Joules, reflecting the energy due to the object's position above a reference level.
Explanation:The relationship between height (h) and gravitational potential energy (GPE) is directly proportional. This means, as an object is raised to a higher elevation above the ground, its GPE increases. The formula for calculating GPE is G.P.E. = mgh, where m represents the mass of the object in kilograms, g is the acceleration due to gravity (approximately 10 m/s² on Earth's surface), and h is the height in meters. The unit of GPE is Joules, which quantifies the energy associated with the object's position in the gravitational field.
In physics, only the change in GPE (ΔGPE) is of significance, which is measured as the difference in energy when an object's height changes relative to a reference level. For instance, if a 0.500-kg mass from a cuckoo clock is lifted by 1.00 m, its GPE changes by mgh. The concept of GPE is vital in various applications, including understanding how energy is conserved within systems influenced by gravitational forces.
a swimmer can swim in still water at a speed of 9.50 m/s. he intends to swim directly across the river that has a downstream current of 3.75 m/s. what is his velocity relative to the bank?
The relative velocity of swimmer to the bank is [tex]\boxed{10.21\text{ m/s}}[/tex] and [tex]\boxed{21.54^\circ}[/tex] downstream.
Further Explanation:
The swimmer swims across the river from one end to the other. The river is flowing downstream.
The swimmer will cross the river with some relative velocity.
Given:
The velocity of swimmer is [tex]9.50\text{ m/s}[/tex].
The velocity of river is [tex]3.75\text{ m/s}[/tex] downstream.
Concept:
Consider the direction of velocity of swimmer in positive x-direction.
The velocity of swimmer in vector form:
[tex]V_s=9.50\hat i[/tex]
Consider the direction of downstream current of river in negative y-direction.
The velocity of downstream current in vector form:
[tex]V_r=- 3.75\hat j[/tex]
The relative velocity of swimmer to the bank is the resultant of two vectors in x and y direction.
Magnitude of relative velocity:
[tex]{V_{sr}}=\sqrt{V_r^2+V_s^2}[/tex]
Substitute [tex]9.50\text{ m/s}[/tex] for [tex]V_s[/tex] and [tex]3.75\text{ m/s}[/tex] for [tex]V_r[/tex] in above equation.
[tex]\begin{aligned}{V_{sr}}&=\sqrt{3.75^2+9.50^2}\text{ m/s}\\&=10.21\text{ m/s}\end{aligned}[/tex]
The magnitude of relative velocity of swimmer is [tex]10.21\text{ m/s}[/tex] .
The direction of relative velocity:
[tex]\theta={\tan^{-1}}\left({\dfrac{{{V_r}}}{{{V_s}}}}\right)[/tex]
Substitute [tex]9.50\text{ m/s}[/tex] for [tex]V_s[/tex] and [tex]-3.75\text{ m/s}[/tex] for [tex]V_r[/tex] in above equation.
[tex]\begin{aligned}\theta&={\tan^{-1}}\left({\dfrac{{{-3.75}}}{{{9.50}}}}\right)\\&=21.54^\circ\end{aligned}[/tex]
The direction of relative velocity is [tex]21.54^\circ[/tex] downstream.
Thus, the relative velocity of swimmer to the bank is [tex]\boxed{10.21\text{ m/s}}[/tex] and [tex]\boxed{21.54^\circ}[/tex] downstream.
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Answer Details:
Grade: Middle School
Subject: Physics
Chapter: Scalars and vectors
Keywords:
Swimmer, still, water, speed, 9.50 m/s, intends, directly, river, downstream, current, 3.75 m/s, velocity, relative, bank, vector, direction, 21.5degree and 10.21 m/s.
How is our planets giant,thermohaline system of warm and cold water like a massive convection current
which force causes an object to free fall
a) wind
b) fluid forces
c) friction
d) gravity
Suppose a car is traveling at +25.0 m/s, and the driver sees a traffic light turn red. After 0.340 s has elapsed (the reaction time), the driver applies the brakes, and the car decelerates at 7.00 m/s2.
How could a person easily tell which envelope contained four sheets of paper and which contained five sheets without opening the envelopes what assumption did you make in arriving at your answers
You could tell the difference between two envelopes containing 4 and 5 sheets of paper by comparing their weights. An envelope with 5 sheets should feel heavier than the one with 4 sheets, assuming that all materials involved are identical.
Explanation:One way to tell the difference between two envelopes containing 4 and 5 sheets of paper without opening them would be to use weight as a distinguishing factor. Given that the weight of paper is constant, one sheet of paper would add a perceivable amount of weight to an envelope. Therefore, the envelope with 5 sheets should be heavier than the envelope containing 4 sheets. The assumption here is that both the envelopes and the sheets of paper are identical in every other aspect including size, material, weight, etc.
In theory, if you were to hold each envelope in either hand, the difference in weight should be detectable. It's a common practice in mailrooms where workers are adept at figuring out the number of papers inside envelopes just by weight comparison. This method, however, requires a certain level of sensitivity and practice. The real application of this method can vary based on multiple factors such as individual's sensitivity to weight change, uniformity in the weight of the paper etc.
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The mixture use separated was a mixture of iron feelings sand and salt based on your understanding of matter is this mixture a homogenous or mixture or heterogenous mixture
The Greek philosopher Democritus coined what word for a tiny piece of matter that cannot be divided?
A - Element
B - Atom
C - Electron
D - Molecule
If an electric train is travelling south, which way is the smoke going?
What is the result of (6.2 × 10 4) x (3.3 × 10 2) expressed in scientific notation?
The multiplication of (6.2 × 10^4) by (3.3 × 10^2) results in 2.046 × 10^7, when expressed in scientific notation.
Explanation:The result of the multiplication (6.2 × 104) × (3.3 × 102), expressed in scientific notation, involves multiplying the coefficients (6.2 and 3.3) and then adding the exponents of 10 (4 and 2). It's important to recall that we must perform both steps to arrive at the correct answer in scientific notation.
The product of the coefficients is 20.46 and when we add the exponents the result is 106. So the multiplication gives us 20.46 × 106, but in correct scientific notation, we want the coefficient to be between 1 and 10. To achieve this we adjust the coefficient to 2.046 and increase the exponent by 1, giving us the result: 2.046 × 107.
PLEASE ANSWER VERY IMPORTANT
A good scientist keeps an open mind to every idea and explanation, even if they do not appear to be relevant to the outcome of the current experiment
Chalk is an ionic compound. Which is a property of all ionic compounds that makes chalk particularly useful for writing on a chalkboard?
Answer:
Hardness and brittleness
Explanation:
Ionic substances form crystal lattices which allow the compounds to be hard because of the strong attractions between positive and negative ions in the lattice. When pressure is applied to the compound like chalk , it may force ions of the same charge together ( i.e. positive to positive). This is called electrostatic repulsion which is able to break the crystal lattice allowing one to write on the chalkboard.
compare and contrast potential and kinetic energy
Potential energy is stored energy due to an object's position or state, while kinetic energy is the energy of an object in motion. They differ in their state, with potential energy being at rest and kinetic energy being in action. However, both can be transformed into each other.
Explanation:Potential energy and kinetic energy are both forms of mechanical energy, but they are different in many ways. Potential energy is stored energy that an object has due to its position or state, like a rock perched at the top of a hill has gravitational potential energy. It has the potential to convert into kinetic energy but for now, it remains at rest.
On the other hand, kinetic energy is the energy of motion. An object in motion has kinetic energy— for example, a moving car or a flowing river has kinetic energy. Unlike potential energy, it is already in action. So the key difference is that potential energy is stored, while kinetic energy is in motion.
However, they are similar in that they both can be transformed into each other. For instance, when that rock on the hill begins to roll downhill, its potential energy is converting into kinetic energy.
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What are some tools that are used for tornadoes
Which statement describes what happens when Bret runs up a flight of stairs?
His kinetic energy increases.
His potential energy decreases.
His kinetic energy is converted into potential energy.
His potential energy is converted into kinetic energy.
Answer:
The answer is C) His kinetic energy is converted into potential energy.
what two properties show that a drink is a fluid
Answer:
Two properties that show that the drink is a fluid/liquid include its retention of volume and its conformation to the shape of its container.
Explanation:
predict which will fall to the ground faster a crumpled paper or flat sheet of paper
Help please
Any unit of distance divided by any unit of time creates a unit of _____.
A. speed
B. velocity
C. position
D. acceleration
if a plane was flying at a speed of 400 km/ hr and 2 min later has slowed to 100 km/hr to land what is the acceleration
_____ is the total kinetic energy of particles in an object.
Describe a situation in which the displacement f a roller skater is 0 km, but the distance traveled is 2 km.