College Physics Prob:?

Question

A 1.6kg ball is attached to the end of a 0.40. string to form a pendulum. This pendulum is released from rest with the string horizontal. At the lowest point of its swing, when it is moving horizontally, the ball collides with a 0.80kg block initially at rest on a horizontal frictionless surface. The speed of the block just after the collision is 3.0m/s. What is the speed of the ball just after the collision?

Answer 1

Using conservation of energy. Find the speed of the 1.6 kg ball the instant before collision

1.6*9.8*0.4=.5*1.6*v^2
v=2.8 m/s

using conservation of momentum
1.6*2.8=1.6*v+0.8*3
v=1.3 m/s

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