A trolley of mass is moving with a speed of

PHYSICS · Single correct · A Level · Physics · Mechanics and materials · Mechanics and materials

Problem

A trolley of mass

12\,\text{kg}

is moving with a speed of

2\,\text{m/s}

. After unloading some boxes, its mass becomes

6\,\text{kg}

and its speed rises to

6\,\text{m/s}

. What is its kinetic energy after the unloading? (a)

54\,\text{J}

(b)

216\,\text{J}

(c)

108\,\text{J}

(d)

96\,\text{J}