Which of the following is an equation of uniformly accelerated motion?
- A.v squared equals u squared plus 2as
- B.v equals u plus as
- C.s equals ut plus at
- D.v equals u plus at squared
Correct answer
Explanation
The correct answer is A. The three equations of uniformly accelerated motion are v equals u plus at, s equals ut plus half of a t squared, and v squared equals u squared plus twice a s, where u is the initial velocity, v the final velocity, a the acceleration, t the time and s the distance covered.
Option B replaces time with distance in the first equation, which is wrong because the first equation connects velocity with time, not with distance. Option C omits the half and squares nothing, so it is not the second equation. Option D squares the time in the first equation, which belongs to the second equation instead. The third equation is the useful one when time is not given, and the choice of equation in a numerical question is decided entirely by which of the five quantities the problem does not mention.
Read the full article: Motion, Force and Newton's Laws: Formulas and Facts
Practice Questions
View allNewton's first law of motion is also known by which name?
- A.Law of inertia
- B.Law of momentum
- C.Law of action and reaction
- D.Law of gravitation
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The first law states that a body continues in its state of rest or of uniform motion in a straight line unless an unbalanced external force acts on it, which is exactly the property called inertia.
Read the full explanation →Which of the following is a vector quantity?
- A.Distance
- B.Speed
- C.Displacement
- D.Time
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It is the shortest distance from the starting point to the finishing point together with the direction of that straight line, so it has both magnitude and direction and is therefore a vector.
Read the full explanation →The equation force equals mass multiplied by acceleration follows from which law of motion?
- A.First law
- B.Second law
- C.Third law
- D.Law of conservation of energy
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It states that the rate of change of momentum of a body is proportional to the applied force and takes place in the direction of the force.
Read the full explanation →The recoil of a gun when a bullet is fired is explained by the conservation of which quantity?
- A.Energy
- B.Linear momentum
- C.Mass
- D.Electric charge
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Before firing, the gun and the bullet are at rest, so the total momentum of the system is zero.
Read the full explanation →What is the SI unit of momentum?
- A.Newton
- B.Joule
- C.Kilogram metre per second
- D.Newton per second
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Momentum is the product of mass and velocity, so its unit is the unit of mass multiplied by the unit of velocity, that is kilogram multiplied by metre per second.
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