A truck travels eastward along a straight

PHYSICS · Subjective · CBSE · Physics · Work, Energy and Power · Work, Energy and Power

Problem

A truck travels eastward along a straight, smooth road with a constant speed of

20\,\text{m s}^{-1}

relative to the ground. Inside the truck, a small block

P

of mass

0.50\,\text{kg}

slides on the frictionless horizontal floor with a speed of

6\,\text{m s}^{-1}

directed towards the rear of the truck. It collides head-on with another block

Q

of mass

1.0\,\text{kg}

that is initially at rest relative to the truck. The coefficient of restitution between

P

and

Q

0.40

. (i) Taking the ground as reference, write the initial momenta of blocks

P

and

Q

just before the collision. (ii) Determine the speeds and directions of both blocks with respect to the ground immediately after the collision. (iii) Calculate the loss of kinetic energy of the system as measured in the ground frame. (iv) Repeat the calculation of loss of kinetic energy in the truck frame and show that it is the same as the value obtained in part (iii).

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