Question

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

• A. 0.18 N
• B. 1.8 N
• C. 2.1 N
• D. 0.32 N

Answer 1

The correct option is A 0.18 N

As we know that from second law of motion
$F=\frac{\Delta p}{\Delta T}=\frac{m\Delta v}{\Delta T}$
$\Delta v=v_f-v_i=3.5-2=1.5m/s$
Sp, force $\left(F\right)=\frac{m\times v}{t}=\frac{3\times 1.5}{25}=0.18N$