Answer TRUE OR FALSE 17) Kinetic energy is proportional to speed. 18) The work r
ID: 1498844 • Letter: A
Question
Answer TRUE OR FALSE
17) Kinetic energy is proportional to speed.
18) The work required to stretch a spring changes linearly with the amount of stretch.
19) If a force is directed perpendicular to the displacement, no work is done by that force.
20) A force can be exerted on an object and yet do no work.
21) Work is a vector quantity.
22) In an inelastic collision, the initial kinetic energy is less than the final kinetic energy.
23) The impulse delivered to an object is equal to the change in the object's velocity.
24) In a one-dimensional elastic collision of two identical masses, the masses always exchange velocities.
25) In any elastic head-on collision, the relative speed of the two objects after the collision has the same magnitude (but opposite direction) as before the collision, no matter what the masses are.
Explanation / Answer
17.) True. The kinetic energy is given as 0.5mv2. Hence it is proportional to the speed.
18.) False. The work required to stretch a spring is given as 0.5kx2.
19.) False. If the force is directly proportional to displacement, that is, F = kx, then the work done is given as 0.5kx2
20.) True. During a circular motion, the force is towards the centre of the circle, while the work done is zero.
21.) False. Work is a scalar quantity.
22.) True. The kinetic energy is lost in inelastic collision, henc the final kinetic energy is smaller than initial.
23.) False. The impulse delivered to an object is equal to the change in momentum of the body.
24.) True. For the momentum of the system to remain conserved the velocities of the body interchange.
25.) True. For elastic collision, the ratio of relative velocities after and before the collision is same.
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