1. Unit 09 “The Law of the Conservation of Momentum” Introduction to Problem Solving

2. Easy Problem Solving 1.A 50.0kg girl jumps into a 100kg raft at rest on the water. If the velocity of the girl is 4.00m/s as she jumps, what is the final velocity of the girl and the raft? 1 st Draw a Picture

3. Easy Problem Solving 1.A 50.0kg girl jumps into a 100kg raft at rest on the water. If the velocity of the girl is 4.00m/s as she jumps, what is the final velocity of the girl and the raft? G R G R m G = 50.0kg V G = 4.00m/s m R = 100kg V R = 0m/s m G V G + m R V R = (m G + m R )V f 200kgm/s = (150kg)V f 1.33m/s = V f 1 st Draw a Picture BeforeAfter m G = 50.kg m R = 100kg V f = ? (50.0kg)(4.00m/s)+(100.0kg)(0m/s) = (50.0kg +100kg)(V f )

4. Easy Problem Solving 2.A 63.0kg astronaut throws a 5.0kg hammer in a direction away from the shuttle with a speed of 18.0m/s, pushing the astronaut back to the shuttle. Assuming that the astronaut and hammer start from rest, find the final speed of the astronaut after throwing the hammer.

5. BeforeAfter Easy Problem Solving 2.A 63.0kg astronaut throws a 5.0kg hammer in a direction away from the shuttle with a speed of 18.0m/s, pushing the astronaut back to the shuttle. Assuming that the astronaut and hammer start from rest, find the final speed of the astronaut after throwing the hammer. 1 st Draw a Picture A H A H m A = 63.0kg V A = 0m/s m H = 5.0kg V H = 0m/s m A = 63.0kg V A = ? m H = 5.0kg V H = 18m/s m A V A + m H V H = m A V A + m H V H (63.0kg)(0m/s)+(5.0kg)(0m/s) = (63.0kg)V A + (5.0kg)(18.0m/s) 0kgm/s = (63.0kg)V A + 90.0kgm/s -90.0kgm/s = (63.0kg)V A -1.43m/s = V A +90kgm/s -90kgm/s

6. Easy Problem Solving 3.A 15.0kg cart moving to the right with a speed of 4.0m/s collides with a 6.5kg cart moving to the left with a speed of 2.0m/s. If the carts stick together, find the final speed of the two carts.

7. Easy Problem Solving 1 st Draw a Picture BeforeAfter 1 2 A H m 1 = 15.0kg V 1 = 4.0m/s m 2 = 6.5kg V 2 = -2.0m/s m 1 = 15.0kg V f = ? m 2 = 6.5kg m 1 V 1 + m 2 V 2 = (m 1 + m 2 )V f (15.0kg)(4.0m/s)+(6.5kg)(-2.0m/s) = (15.0kg + 6.5kg)(V f ) 60kgm/s + (-13.0kgm/s) = (21.5kg)V f 47.0kgm/s = (21.5kg)V A 2.19m/s = V A 3.A 15.0kg cart moving to the right with a speed of 4.0m/s collides with a 6.5kg cart moving to the left with a speed of 2.0m/s. If the carts stick together, find the final speed of the two carts. 60kgm/s -13.0kgm/s = (21.5kg)V f