Question

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

• A. $625N$
• B. $6250N$
• C. $62.50N$
• D. $6.250N$

Answer 1

The correct option is B $6250N$

Given,

$m=10g=0.01kg$

$u=250m/s$

$s=5cm=0.05m$

$v=0m/s$

3rd equation of motion,

$v^2-u^2=2as$

$0^2-(250{)}^2=2\times 0.05\times a$

$a=\frac{62500}{0.1}=-625000m/s^2$

The magnitude of force exterted by the tree limb is,

$F=ma$

$F=0.01\times 625000=6250N$

The correct option is B.