An indestructible bullet 2.00 cm long is fired straight through a board that is 10.0 cm thick. The bullet strikes the board with a speed of 480 m/s...

An indestructible bullet 2.00 cm long is fired straight through a board that is 10.0 cm thick. The bullet strikes the board with a speed of 480 m/s and emerges with a speed of 265 m/s. (To simplify, assume that the bullet accelerates only while the front tip is in contact with the wood.)(a) What is the average acceleration of the bullet through the board?