SOLUTION: Two ice skaters stand face to face and "push off" and travel directly away from each other. The boy has a velocity of 5 m/s and he weighs 740 N. The girl weighs 490 N. What is

Question 460418: Two ice skaters stand face to face and "push off" and travel directly away from each other. The boy has a velocity of 5 m/s and he weighs 740 N. The girl weighs 490 N. What is the girl's velocity?
Answer by richard1234(7193) (Show Source): You can put this solution on YOUR website!
Assuming no frictional losses, the total momentum within the system will remain unchanged, and it will remain zero (zero because we are accounting for velocities in different directions, not the actual speeds).

The masses of the boy and girl can be found by taking 740 N and 490 N and dividing each by g. Hence, we can find the momentum of each person:

The momentum of the girl is

The two momenta add up to zero so we can solve for v_girl:

(negative because the velocity is in the opposite direction of the boy's)

(Excuse my weird notation, but I decided not to divide 740, 490 by 9.81 simply because it is not needed and g will cancel out anyway. I just left it in there along with the units since the units have to be consistent.)
RELATED QUESTIONS
Two hockey players are facing each other on the ice they push apart with a force of... (answered by ikleyn)

Hello, these are physics problems. Help please 1. A 0.22 kg red striped pool ball is... (answered by mananth,ikleyn)

In a 100 page book, pages 2 and 3 face each other. Similarly, pages 4 and 5 and 6 and 7... (answered by KMST)

A new toy store is giving away 20 model airplanes: 9 are red, 6 are white, and 5 are... (answered by stanbon)

A big room is constructed so that the ceiling is a dome that is semielliptical in shape.... (answered by ikleyn)

Suppose that for the couple in the figure below, you were told that the girl's mass was... (answered by mananth)

Dayton is mountain climbing with Leo and has just climbed a 15-meter vertical rock face.... (answered by Alan3354)

Mia is mountain climbing with Helen and has just climbed a 33-foot vertical rock face.... (answered by ikleyn)

If a card is drawn from an ordinary deck, find he probability of drawing each of the... (answered by rothauserc)