Question

A man is waiting for a bus. What is the work done by the man on the box when he runs carrying the box accelerating to a speed of $3m{s}^{-1}$ from rest to catch the bus? Mass of box = 20 kg.

• A. $200J$
• B. $60J$
• C. $90J$
• D. $180J$

Answer 1

Answer: (C)

$90J$

$K.E=0.5m{v}^2$.
$K.E=0.5\times 20\times 9=90J$
By work energy theorem, Work done $=$change in kinetic energy