Answer:
The block+bullet system moves 4 m before being stopped by the frictional force.
Explanation:
Using the law of conservation of llinear momentum and the work energy theorem, we can obtain this.
According to Newton's second law of motion
Momentum before collision = Momentum after collision
Momentum before collision = (0.02×400) + 0 (stationary block)
Momentum before collision = 8 kgm/s
Momentum after collision = (2+0.02)v
8 = 2.02v
v = 3.96 m/s.
According to the work-energy theorem,
The kinetic energy of the block+bullet system = work done by Friction to stop the motion of the block+bullet system
Kinetic energy = (1/2)(2.02)(3.96²) = 15.84 J
Work done by the frictional force = F × (distance moved by the force)
F = μmg = 0.2(2.02)(9.8) = 3.96 N
3.96d = 15.84
d = (15.84/3.96) = 4 m
