Question

The moment P (in $kgm{s}^{-1}$) of a particle is varying with time t (in second) as $p=2+3t^2$. The force acting on the particle at $t=3s$ will be

• A. 18 N
• B. 54 N
• C. 9 N
• D. 15 N

Answer 1

The correct option is A 18 N

Given,

$p=2+3t^2$

From Newton's second law,

$F=\frac{dp}{dt}$

$F=\frac{d(2+3t^2)}{dt}$

$F=0+6t=6t$

At $t=3s$

$F=6\times 3=18N$

The correct option is A.