Momentum and Energy problem, conservation.?

AI Thread Summary
The discussion revolves around a physics problem involving a pendulum and a bullet, focusing on the conservation of momentum and energy. The initial scenario describes a 9.99 kg pendulum bob being struck by a 0.01 kg bullet, resulting in a maximum vertical displacement of 4.60 cm after the collision. The calculated velocity of the bullet before impact is 949 m/s. A follow-up question considers an elastic collision with the same bullet, asking how high the pendulum would rise, with the answer being 18.4 cm. Participants emphasize the importance of applying conservation principles to solve the problem effectively.
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Homework Statement



A pendulum of 9.99 kg is initially at rest, just skimming the floor below. A bullet of mass 0.01kg is fired at the bob. The bullet collides with the bob and embeds itself, after which the pendulum begins to move. The bullet-bob pendulum reaches the maximum vertical displacement of 4.60 cm.

a) Calculate the velocity of the bullet just before the impact with the bob. (ANS: 949m/s)

b) If a rubber bullet of mass 0.01kg was fired at the 9.99 bob with a speed of 949 m/s, and collided elastically with the bob, how high would the pendulum now rise?

ANS b: 18.4 cm

Homework Equations



P1 = P2 and E1 = E2

The Attempt at a Solution



a) I think we are supposed to use the conservation of momentum and energy to answer this but I cannot do it.

26 minutes ago - 4 days left to answer.
 
Last edited by a moderator:
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You're right. You need to use conservation of momentum and energy. Show us your attempt at applying those principles.
 
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