Collision with an unknown mass and velocity after

AI Thread Summary
A 2 kg block slides on an icy surface at 3 m/s towards a static block of mass M, colliding and reversing direction to -1 m/s. The total kinetic energy remains constant during the collision. The calculations yield a mass M of 4 kg and a final velocity of 2 m/s for mass M after the collision. The solution approach involved applying conservation of momentum and kinetic energy equations. The results were confirmed as correct, addressing concerns about potential calculation errors.
fantisism
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Homework Statement


You slide a 2 kg block on a flat icy surface towards a static block of mass M. Before the collision, the 2 kg mass is moving at 3 m/s. The total kinetic energy is not changed by the collision. After the collision, the 2 kg mass is moving at −1 m/s i.e. opposite to its original direction. Calculate the mass M in kg and the velocity of the mass M after the collision.

Homework Equations


Eq 1.) 0.5mv1i2+0.5Mv2i2=0.5mv1f2+0.5Mv2f2
Eq 2.) mv1i+Mv2i=mv1f+Mv2f

The Attempt at a Solution


I got v2f=2 m/s and M=4 kg. I solved for M for the second equation and substituted that in into the first equation.
 
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fantisism said:

Homework Statement


You slide a 2 kg block on a flat icy surface towards a static block of mass M. Before the collision, the 2 kg mass is moving at 3 m/s. The total kinetic energy is not changed by the collision. After the collision, the 2 kg mass is moving at −1 m/s i.e. opposite to its original direction. Calculate the mass M in kg and the velocity of the mass M after the collision.

Homework Equations


Eq 1.) 0.5mv1i2+0.5Mv2i2=0.5mv1f2+0.5Mv2f2
Eq 2.) mv1i+Mv2i=mv1f+Mv2f

The Attempt at a Solution


I got v2f=2 m/s and M=4 kg. I solved for M for the second equation and substituted that in into the first equation.
What is your question then? That result is correct.
 
ehild said:
What is your question then? That result is correct.
Oh sorry. I just wanted to make sure those were right because I tend to make small simple math errors. Thank you!
 
You are welcome:oldsmile:
 

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