Question

A truck of mass $2\times {10}^3\text{kg}$ is coming towards a wall with a speed of $5\text{m/s}$. It collides with the wall and remain in its contact for $0.02\text{s}$. After collision, it travels in opposite direction, with a speed of $3\text{m/s}$. What force (assuming it to be constant), the wall must have exerted on the truck?

• A. $0.8\times {10}^5\text{N}$
• B. $0.8\times {10}^6\text{N}$
• C. $0.4\times {10}^6\text{N}$
• D. $0.4\times {10}^5\text{N}$

Answer 1

The correct option is B $0.8\times {10}^6\text{N}$

We know that, force,

$F=\frac{\Delta p}{\Delta t}=\frac{p_f-p_i}{\Delta t}=\frac{m(v_f-v_i)}{\Delta t}$

$\Rightarrow F=\frac{2\times {10}^3[5-(-3\left)\right]}{0.02}=0.8\times {10}^6\text{N}$