A roller-coaster cart starts from rest at point

PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials

Problem

400\,\text{kg}

roller-coaster cart starts from rest at point

A

, which is

20\,\text{m}

above the lowest point of a track. It descends to the lowest point

B

(taken as the reference level) and then ascends to point

C

which is

5\,\text{m}

above

B

. During the motion from

A

C

, friction performs

2.0\times10^{4}\,\text{J}

of work opposing the motion. Take

g = 9.8\,\text{m}\,\text{s}^{-2}

. (i) Calculate the speed of the cart at

B

if friction is neglected. (ii) Taking the given work done by friction into account, determine the speed of the cart at

C