Question

A moving body, when given a retardation of $2m{s}^{-2}$, stops in $25s$. What was its initial velocity?

• A. $100m{s}^{-1}$
• B. $12.5m{s}^{-1}$
• C. $50m{s}^{-1}$
• D. None of these

Answer 1

The correct option is C $50m{s}^{-1}$

Initial velocity $=u$, say
Final velocity $\left(v\right)=0$
Retardation $=2m{s}^{-2}$
Time $\left(t\right)=25s$
Retardation = $\frac{u-v}{t}$
or, $2=\frac{u-0}{25}=\frac{u}{25}$
or, $u=50m{s}^{-1}$