Question

A man of mass 60 kg climbs up a 20 m long staircase to the top of a building 10 m high. What is the work done by him? (Take g = 10 m $s^{-2}$ ).

• A. 12 kJ
• B. 6 kJ
• C. 3 kJ
• D. 18 kJ

Answer 1

The correct option is B 6 kJ

Here, $m=60kg$, height $h=10m$

Work done $W=$ change in potential energy $=mgh-0=mgh=60\times 10\times 10=6000J=6kJ$