Momentum, Impulse and Collisions

1. Mar 26, 2015

xRohan1

1. The problem statement, all variables and given/known data
Two hockey players push each other on the ice. The 86-kg skater moves with a velocity of 2.4 m/s. Find the recoil velocity of the 79-kg skater

2. Relevant equations
idk

3. The attempt at a solution
86*2.4=79*v2 v2=2.613 m/s

Second problem
1. The problem statement, all variables and given/known data
A child drops a 5-g marble on the floor. The marble hits the floor with a velocity of -3.13m/s and rebounds with a velocity of 1.87 m/s. What is the marble's change in momentum? What impulse acts on the marble? What is the force of impact if the marble is in contact with the floor for a time of 2.5 x 10^-3s?

2. Relevant equations
idk
3. The attempt at a solution
A) (5*1.87)-(5*-3.13)
B)
C)(5*-3.13)/(2.5*10^-3)=-6260N

2. Mar 26, 2015

haruspex

Can you not express the principle you used below in general terms?
Units?
Are you stuck on this?
You need to use the result from A/B