A block of wood with a mass M = 4.65 kg is resting on a horizontal surface when a bullet with a mass to = 18 g and moving with a speed it = ?25 rnfs strikes it. The coefficient of friction be tween the block and the surface is p = 0.35. The distance the block rnoves across the surface is 1.1n1 A mass m1 = 2.5 kg is connected to another rnass H12 = 4.0 kg by a compressed spring. Both masses are at rest on a frictionless surface. When the spring is released, the masses are pushed apart and a total energy of 16.8 J is given to the two masses. The speed of mass ml is 2.9 rnfs Two objects, one of mass m1 = 2 kg and the second of unknown mass, are connected by a com pressed spring with negligible mass. The system is at rest on a frictionless table. Both objects are -2m-s :6. released simultaneously. ml is observed to recoil with velocity 1"1 = and m2 shots for- ward with velocity l? = im' 5 i' What is the mass of n12? m 1 m : m 1kg