Question

In a children's park, there is a slide which has a total length of $10m$ and a height of $8.0m$. A vertical ladder is provided to reach the top. A boy weighing $200N$ climbs up the ladder to the top of the slide and slides down to the ground. The average friction offered by the slide is three-tenth of his weight. The work done by the slide on the boy as he comes down is

• A. zero
• B. + 600 J
• C. -600 J
• D. +1600 J

Answer 1

Answer: (C)

Force, $F=\frac{3}{10}mg$
As, $W=-Fs$
or $W=-\frac{3}{10}mgs$
or $W=-\frac{3}{10}\times 200\times 10J=-600J$