The ballistic pendulum consists of a block of wood (mass m2=2.5kg) suspended by a wire of negligible mass. A bullet (mass m1=0.01kg) is fired with a speed of ui m/s just after the bullet collides with it, the block (with the bullet in it) has a speed of 4m/s and then swings to a maximum height of hf cm above the initial position. Assuming that air resistance is negligible,
a) Find the initial speed, ui of the bullet?
b) Find the height, hf the pendulum swings?

Question

The ballistic pendulum consists of a block of wood (mass m2=2.5kg) suspended by a wire of negligible mass. A bullet (mass m1=0.01kg) is fired with a speed of ui m/s just after the bullet collides with it, the block (with the bullet in it) has a speed of 4m/s and then swings to a maximum height of hf cm above the initial position. Assuming that air resistance is negligible, 
a) Find the initial speed, ui of the bullet?
b) Find the height, hf the pendulum swings?