Question

A rigid body of mass $m$ kg is lifted uniformly by a man to a height of one metre in $30$ sec. Another man lifts the same mass to the same height in $60$ sec. The work done on the body against gravitation in both the cases are in ratio:

• A. 1 : 2
• B. 1 : 1
• C. 2 : 1
• D. 4 : 1

Answer 1

The correct option is B 1 : 1

$W=F.S$
As work done is independent of time. So, both the man does same work.
Hence, the work done on the body against gravitation are in ratio $1:1$.