A Ballistic Pendulum. ?A 12.0-g rifle bullet is fired with a speed of 380 m/s into a ballistic pendulum with mass 6.00 kg, suspended from a cord 70.0 cm long (see Example 8.8 in Section 8.3). Compute (a) the vertical height through which the pendulum rises, (b) the initial kinetic energy of the bullet, and (c) the kinetic energy of the bullet and pendulum immediately after the bullet becomes embedded in the pendulum.

Solution 43E Step 1: Mass of the bullet is, m 1 12 g = 0.012 kg . Mass of the pendulum is, m = 62kg . Initial speed of the bullet was, v = 380 m/s. 1 Initial speed of the pendulum was, v = 2. By the law of conservation of linear momentum, m 1 1 m v 2 2m + m 1V 2 0.012 × 380 + 0 = 6.012 × V V = 0.758 m/s. This is the velocity of the whole system which consists the pendulum and the bullet.