A bullet of mass 25 g is fired directly at a fixed wooden block of thickness 4 cm and passes through it. When the bullet hits the block, it is travelling horizontally at \(200 \mathrm {~ms} ^ { - 1 }\). The block exerts a constant resistive force of 8000 N on the bullet.
Find the work done by the block on the bullet.
By using the Work-Energy principle,
show that the bullet emerges from the block with speed \(120 \mathrm {~ms} ^ { - 1 }\).