# Homework Help: Need Help with Momentum and Impulse? Need some one smart

1. Nov 27, 2008

### devilz_krypt

Need Help with Momentum and Impulse?!?! Need some one smart......

The only formulas that were provided were

1. I =Δp
2. mΔv
3. I=FΔt
4. KE= 1/2 mv^2
5. PE= mgΔh
6. ΔPE= ΔKE
7. W= F*D
8. W= ΔKE

Momentum Before Collision = Momentum After Collision

9. mava + mbvb = mava + mbvb Elastic Collision
10. mava + mbvb = mavb(v) inelastic collision

The little apostrophe are for subscripts, e.g. m`a, meaning "m" is normal, but the a is a subscript.

Questions
1. A tennis ball may leave the racket of a top player on the serve with a speed of 65 m/s. If the ball's ,*** is .06 kg and it is in contact with the rackt for .03 secs, what is the average force on the ball?

2. A .145 kg basball pitched at 39 m/s is hit on a horzontal line drive straight back towards the pitcher at 52 m/s. If the contact time betwween bat and ball is 1.00 E-3 sec, calculate the average force between the bat and ball contact.

2. Nov 27, 2008

### jumpman11372

Re: Need Help with Momentum and Impulse?!?! Need some one smart......

1) You know the ball starts off at rest, and is then given a hit, which leads to a change in momentum. Impulse is a change in momentum; substitute and use that with the impulse formula to solve for force.

2)Yet again, solve for the change in momentum. Once found, set equal to I=FΔt