Question

A bullet of 10 g, moving at 250 m/s, penetrates 5 cm into a tree limb before coming to rest. Assuming uniform force being exerted by the tree limb, the magnitude of the force is:

• A. 12.5 N
• B. 625 N
• C. 62.5 N
• D. 125 N
• E. 6250 N

Hint:

Use the work-energy theorem to connect force, displacement, and kinetic energy changes.

Answer 1

Answer: (E)

Using the work-energy principle: \[ {Work} = {Force} \times {Distance} = \frac{1}{2} m v^2 \] \[ F \times 0.05 = \frac{1}{2} \times 0.01 \times (250)^2 \] \[ F = \frac{0.5 \times 0.01 \times 62500}{0.05} = 6250 { N} \]