Question

The puck hits and bounces off one of the robots. The 225 kg robot shrugs off the hit and begins skating toward the puck. However, two other robots had the same idea. The first robot is traveling 11.1 m/s toward the puck at the same time that a second robot, which has a mass of 250 kg, is traveling 9.50 m/s toward the puck from the opposite direction. They entangle and 1 collide with a third robot, which has a mass of 200 kg, and is stopped near the puck. What is the momentum and velocity of the 3-robot system?

Answer 1

Here

let the velocity of 3 robot system is vf

Now, as the momentum is conserved during collisions

for the momentum of 3 robot system

momentum of 3 robot system = sum of their initial momentum

momentum of 3 robot system = 225 * 11.1 - 250 * 9.50 + 200 * 0

momentum of 3 robot system = 122.5 Kg.m/s

the momentum of 3 robot system is 122.5 Kg.m/s

let the velocity is vf

Using conservation of momentum

(225 + 250 + 200) * vf = 122.5

vf = 0.181 m/s

the velocity of the 3 robot system is 0.181 m/s