A ballistic pendulum which is made from a block (m2 = 2.50 kg) suspended by a wire of negligible mass. A bullet (m1 = 0.0200 kg ) is fired with a speed. The bullet will collide with the block and embed itself in the block. Immediately after the collision the block (with the bullet in it) has a speed v' and then swings to a maximum height of 0.850 m above the initial position. See the diagram below. a) Find an expression for v1. b) Find an expression for the energy right at the start of the collision and after it has risen 0.850 m. c) Solve for v1 assuming that air resistance is negligible.