Figure \(\PageIndex{1}\): The ballistic pendulum. (a) Just before the collision, the pendulum is vertical and at rest; the bullet is moving at speed \(v\). (b) After the collision, the bullet has embe...Figure \(\PageIndex{1}\): The ballistic pendulum. (a) Just before the collision, the pendulum is vertical and at rest; the bullet is moving at speed \(v\). (b) After the collision, the bullet has embedded itself into the block. First, the bullet embeds itself into the wooden block; this is a perfectly inelastic collision so the speed \(v_{0}\) of the block-bullet combination just after the bullet hits the block is given by Eq. (31.2.4):
