Question

A block of mass 2 kg, placed on a long frictionless horizontal table, is pulled horizontally by a constant force F. It is found to move 10 m in the first 2 s. Find the magnitude of the force F.

Answer 1

Initial velocity, $u=0$
Acceleration, $a=\frac{F}{m}=\frac{F}{2}$
Time, $t=2s$
Displacement, $s=10m$
Applying the second equation of motion,
$s=ut+\frac{1}{2}a{t}^2\Rightarrow 10=\left(\frac{1}{2}\right)\left(\frac{F}{2}\right)\times 2\times 2\Rightarrow F=10N$