a boy of mass 45 kg is on a moving ice sled a of mass 30 kg at a speed

Question

A boy of mass 45-kg is on a moving ice sled A of mass 30-kg at a speed 10 mis eaos(i) on a frictionless frozen lake bed. He jumps off sled A with a relative speed 2.0 m/s east with respect to the sled and lands on another identical ice sled B at rest. a) What is the speed of sled A after the boy jumps off it? According to Newton's 2nd law, linear momentum must take an inertia reference frame ( no acceleration) as reference. Ground is a relative good choice. So all velocities must be with respect to the ground when express P=mV The horizontal linear momentum of the system (boy+sled A) is conserved (before and after the boy jumps off sled A due to net external force is zero ( no contact and air friction on the system). b) What is the speed of the sled B after the boy lands on it?