Physics - NLM Question with Solution | TestHub

The impulse equals the area under the F-t graph, and it equals the change in momentum.

From t = 0 to 10 s the force grows linearly from 0 to 20 N:

$${\mathrm{J}}_1=\frac{1}{2}\times 10\times 20=100\mathrm{N}\cdot \mathrm{s}$$

$$\Delta {\mathrm{v}}_1=\frac{{\mathrm{J}}_1}{\mathrm{m}}=\frac{100}{1}=100{\mathrm{ms}}^{-1}$$

So the velocity rises from 10 m/s to 110 m/s at t = 10 s.

From t = 10 to 20 s the force is -10 N, giving impulse -100 N·s, which only brings the velocity back down. Hence the maximum velocity during the period is

$${\mathrm{v}}_{\max }=110{\mathrm{ms}}^{-1}$$

Correct option: (B).