A student performs a ballistic pendulum experiment using an apparatus. Initially the bullet is fired at the block while the block is at rest (at its lowest swing point). After the bullet hits the block, the block rises to its highest position, and continues swinging back and forth.

The following data is obtained: the maximum height the pendulum rises is 5.1 cm, the mass of the bullet is 76 g, and the mass of the pendulum bob is 873 kg. The acceleration of gravity is 9.8 m/s2.

1. Find the final velocity of the system (m1+m2) immediately after the collision and before the pendulum starts to swing upwards. Answer in units of m/s.

2.Find v1, the initial speed of m1. Answer in units of m/s.