Question

A block of mass m = 0.1 kg is released from a height of 4 m on a curved smooth surface. On the horizontal surface path AB is smooth and path BC offers coefficient of friction μ = 0.1. If the impact of block with the vertical wall at C be perfectly elastic, the total distance covered by the block on the horizontal surface before coming to rest will be (take g = 10ms^-2)

• A. 29 m
• B. 49 m
• C. 59 m
• D. 109 m

Answer 1

Answer: (C)

59 m

Answer 2

KE attained by block at B = mgh = 4J

Work done by friction force on path BC = (μmg)(BC) = 0.2 J

On the other horizontal surface block can make total forward and backward

$\left( \frac{4}{0.2} \right) = 20$ trips. but last time it will stop at B

∴ Distance covered = 20 × (AB + BC) − AB = 59 m.

Hence the correct choice is