A ball rests on the floor of a train that moves east at relative to the ground

PHYSICS · Single correct · CBSE · Physics · Motion in a Plane · Motion in a Plane

Problem

0.50\,\text{kg}

ball rests on the floor of a train that moves east at

18\,\text{m/s}

relative to the ground. The ball is then thrown forward so that its speed relative to the train becomes

5.0\,\text{m/s}

. A car on a nearby road travels west (opposite the train’s motion) at

12\,\text{m/s}

relative to the ground. What is the change in the ball’s translational kinetic energy as measured by the driver in the car? (a)

5.0\times10^{1}\,\text{J}

(b)

3.1\times10^{2}\,\text{J}

(c)

8.1\times10^{1}\,\text{J}

(d)

1.6\times10^{2}\,\text{J}