Question

A force of 20 N acting on a body of mass 10 kg is found to double its velocity in 8 s. Find its initial velocity?

• A. 6 m s${}^{-1}$
• B. 16 m s${}^{-1}$
• C. 8 m s${}^{-1}$
• D. 10 m s${}^{-1}$

Answer 1

The correct option is B 16 m s${}^{-1}$

F $=$ 20 N, m $=$ 10 kg, t $=$ 8s
u, v $=$ 2u
$F=m\left(\frac{v-u}{t}\right)$
$20=10\left(\frac{2u-u}{8}\right)$
$u=16m{s}^{-1}$