Math Is Fun Forum

Kurtz

Member

Registered: 2007-10-01

Posts: 27

Conservation of Momentum

Each croquet ball in a set has a mass of .50 kg. The green ball, traveling at 12.0 m/s, strikes the blue ball, which is at rest. Assuming that the balls slide on frictionless surface and all collisions are head-on, find the final speed of the blue ball in each of the following situations:

a. The green ball continues moving after the collision at 2.4 m/s in the same direction.

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I am a mathemagician. You ask why? I point up

mathsyperson

Moderator

Registered: 2005-06-22

Posts: 4,900

Re: Conservation of Momentum

As the croquet balls have the same masses, conservation of momentum in this case can be simplified to conservation of velocity.

Before the collision, the combined velocity of both balls was 12 + 0 = 12m/s.
Afterwards, the green ball has v = 2.4m/s and the total is still 12, so it's a simple matter to work out what speed the blue ball must be going at.

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Why did the vector cross the road?
It wanted to be normal.

Kurtz

Member

Registered: 2007-10-01

Posts: 27

Re: Conservation of Momentum

thanks.

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I am a mathemagician. You ask why? I point up