Conservation of energy and momentum homework

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In an elastic collision involving a 2.0 kg ball at rest and a 5.0 kg ball moving at 10.0 m/s, conservation of momentum and energy principles must be applied to find the final speeds of both balls. The initial momentum and kinetic energy of the system should be calculated before the collision, and then set equal to the final momentum and kinetic energy after the collision. The equation v1 = 2m1/(m1 + m2) is not correctly formatted for this scenario, as it does not account for the initial velocities. Two equations will be derived from the conservation laws to solve for the unknown velocities of both balls. Proper units for speed must also be ensured throughout the calculations.
tica86
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A 2.0 kg ball at rest is struck head-on by a 5.0 kg ball moving along a track at 10.0 m/s in an elastic collision. What is the speed of the 5.0 kg ball and the 2.0 kg ball after the elastic collision?

----I'm sure this is a pretty simple question but I don't where to start.
Is the following equation correct?

v1= 2m1/m1+m2 ?

please help
 
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tica86 said:
v1= 2m1/m1+m2 ?

What are the units of speed? Does the RHS of this equation have those units?

You will need to use conservation of energy and momentum to solve this. Compute the momentum and energy of the system before and after the collision, using symbols to represent the unknown velocities. You will have 2 equations to solve for the 2 unknown speeds.
 

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