Question

The force – time graph of an impulse acting on a block of mass 0.02 kg is as shown. If the block initially started from rest, what is its velocity once the force ceases to act on it.

• A. $Zero$
• B. $2m{s}^{-1}$
• C. $5m{s}^{-1}$
• D. $3m{s}^{-1}$

Answer 1

The correct option is C $5m{s}^{-1}$

I = area under f – t graph
$=\frac{1}{2}\times 0.1\times 2=0.1Ns.$
Also
$I=p_f-pi$
$I=m\left(V_f\right)-m\left(0\right)$
$\Rightarrow V_f=\frac{I}{m}$
$=\frac{0.1}{0.02}$
$=5m{s}^{-1}$