Question

A body of mass 6kg is under a force which causes displacement in it given by $S = \frac { t ^ { 2 } } { 4 }$ metres where t is time. The work done by the force in 2 seconds is

• A. 12 J
• B. 9 J
• C. 6 J
• D. 3 J

Answer 1

Answer: (D)

3 J

Answer 2

$s = \frac { t ^ { 2 } } { 4 }$ ∴$d s = \frac { t } { 2 } d t$

Now