Question

A block $A$, whose weight is $200N$, is pulled up a slope of length $5m$ by means of a constant force $F(=150N)$ as illustrated in the figure.The difference in work done by the force and the increase in potential energy of the block is :

• A. $0J$
• B. $150J$
• C. $750J$
• D. $600J$

Answer 1

The correct option is B $150J$

$W=F\times s$
Here angle between force and displacement is 0 degree.Force applied due to weight of body is zero as in this case gravitational force and displacement are perpendicular.
$F=150N;S=5m$.
$W=150\times 5=750J$
$P.E=m\times g\times h$
$m\times g=200N;h=3m$ because one of the perpendicular side has length of 3 m
$P.E=200\times 3=600J$
Hence difference is $750-600=150J$.