What are the solutions for these momentum/impulse problems?

[DLxX]

I need help with this problem.

1) A 0.145kg baseball pitched at 39m/s is hit on a horizontal line drive straight back toward the pitcher at 52m/s. If the contact time between bat and ball is 1.00 X 10^-3s, calculate the average force between the ball and bat during contact.

And for this problem I need to know if the answers I got were correct.

2) A golf ball of mass .045kg is hit off the tee at a speed of 45m/s. The golf club was in contact with the ball for 5.0 X 10^-3s. Find (a) the impulse imparted to the golf ball, and (b) the average force excerted on the ball by the golf club.

This is what I got.

BTW The 5.0 X 10^-3 is my way of showing scientific notion on the computer.
Impulse = 2.03
Average Force = 406

 

[Leong]

Your answers for the second question are correct but if you want to follow the rules of significant figures, round them to 2 significant figures only.
If you can find the average force for the second question, i don't see why you çan't find for the first question.

 

[DLxX]

Your answers for the second question are correct but if you want to follow the rules of significant figures, round them to 2 significant figures only.
If you can find the average force for the second question, i don't see why you çan't find for the first question.

Well in the first question the ball is pitched to the batter, while in the second question the ball starts of stationary.

 

[Leong]

well, what is the formula you use to find the average force in the second question ?

 

[DLxX]

well, what is the formula you use to find the average force in the second question ?

Fnet = Tri P / Tri T

The Tri being a triange which means P final minus P initial and P meaning Momentum with T meaning Time.

 

[Leong]

$$F_{net}=m*\frac{v-u}{t}$$
v is the final velocity and u is the initial velocity of the baseball. the direction of v is opposite to the direction of u. Insert the appropriate sign after you have choosen your 1-D reference frame.