A girl jumps from a tree onto the ground. As she falls she speeds up.Explain in details how the law of conservation of momentum applies in this case?
Can I consider the girl and the earth(the ground) as a system?? Why or why not??
PLEASE HELP ME WITH MOMENTUM PROBLEMS. I would be so happy if you can tell me some advices about learning momentum. Thanks in advance!!!
2007-08-13 01:22:51 · 3 answers · asked by GooGi 1 in Science & Mathematics ➔ Physics
After looking at "The One Who Knows"' answer. I'm still confused... :(
If momentum before impact(hit the ground) is mv+MV=mv+M0=mv,m is mass of the girl and M is mass of earth, assume downward is positive direction.
Then after impact, the girl is at rest I think. If the momentum is conserved, then the earth should moves downward a liiiiiiitle bit. Am i right???
2007-08-13 02:02:03 · update #1
When the girl hits the ground, the momentum is mass x velocity where mass is the mass of the girl. Since momentum is conserved, after the impact, the earth moves a weebit (microscopic and difficult to detect) and the girl also moves upward a little due to recoil.
Remember that the collision is inelastic. So, some energy is absorbed.
Explaining these is possible if I know in which standard of school or college you are studying.
2007-08-13 01:35:20 · answer #1 · answered by Swamy 7 · 0⤊ 0⤋
momentum is simply a collision of two objects.
Mass1*Velocity1=Mass2*Velocity2
In this case, the girl pushes off of the tree. Her foot and the tree are colliding. However, the mass of the tree is so great that there is no velocity, plus its' roots hold it into the ground. That is why there is no velocity from the tree. The reason she accelerates as she falls, is because gravity pulls her down at a rate of 9.81 meters/ second^2
2007-08-13 08:36:05 · answer #2 · answered by Mixed Asian 5 · 0⤊ 0⤋
A human's falling speed is about 120 feet per second, so that all depends on how high is the tree.
2007-08-13 17:59:48 · answer #3 · answered by Anonymous · 0⤊ 0⤋