Question

A constant force acting on a body of mass $3.0kg$ changes its speed from $2.0m{s}^{-1}\text{to}3.5m{s}^{-1}$ in $25s$. The direction of the motion of the body remains unchanged. What is the magnitude of the force (in newton)?

• A. 0.18
• B. 0.36
• C. 0.72
• D. 0.24

Answer 1

The correct option is A 0.18

$m=3kg$

$V_f=3.5m/s$

$V_i=2\sec$

$V_f-V_i=at$

$\Rightarrow 3.5-2=9\left(25\right)$

$\Rightarrow a=\frac{1.5}{25}$

$\therefore F=ma=\frac{3\times 1.5}{25}$

$=\frac{4.5}{25}=0.18N$

Hence,

option $\left(A\right)$ is correct answer.