2009-11-28, 07:16 PM
In Physics we've just started on momentum. Here's a problem we did in class.
![[Image: 1zbfccm.jpg]](http://i49.tinypic.com/1zbfccm.jpg)
You may stand in awe at my awesome drawing skills.
Ball is moving at 200 m/s and has a mass of 2kg. Person about to get hit has a mass of 50 kg.
Frictionless surface.
How fast does the person move after the cannon ball transfers it's momentum?
Since p = mv, and momentum is conserved,
2 kg * 200 m/s = 50 kg * x
Solve for x and we conclude the poor sucker moves at 8 m/s.
(I think)
My question is: "How fast does he accelerate?"
I know he doesn't magically go from 0 m/s to 8. Teacher told me you'd need to know more information.
So 1) what else, if anything, do you need to know and 2) how would you work the acceleration out if you had all the required variables?
You may stand in awe at my awesome drawing skills.
Ball is moving at 200 m/s and has a mass of 2kg. Person about to get hit has a mass of 50 kg.
Frictionless surface.
How fast does the person move after the cannon ball transfers it's momentum?
Since p = mv, and momentum is conserved,
2 kg * 200 m/s = 50 kg * x
Solve for x and we conclude the poor sucker moves at 8 m/s.
(I think)
My question is: "How fast does he accelerate?"
I know he doesn't magically go from 0 m/s to 8. Teacher told me you'd need to know more information.
So 1) what else, if anything, do you need to know and 2) how would you work the acceleration out if you had all the required variables?