Average Force Applied by Catcher

[Jtappan]

Homework Statement

0.15 kg baseball is pitched with a speed of 36 m/s (79.2 mph). When the ball hits the catcher's glove, the glove moves back by 4.9 cm (1.96 in.) as it stops the ball.
(a) What was the change in momentum of the baseball?
5.4 kg·m/s opposite the ball's direction of motion
(b) What impulse was applied to the baseball?
5.4 kg·m/s opposite the ball's direciton of motion
(c) Assuming a constant acceleration of the ball, what was the average force applied by the catcher's glove?
Magnitude _____ kN opposite the ball's direction of motion

Homework Equations

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The Attempt at a Solution

i got everything except the magnitude of the force applied by the glove... i don't know how to do this when i have to relate distance to this problem.

 

[Doc Al]

Use the distance and speed to figure out how much time it took for the catcher to stop the ball.

 

[Jtappan]

i keep doing this problem and it does not work out. I don't know what I am doing wrong. for the time i get .13637.

 

[Doc Al]

That's quite a bit off. Show how you did the calculation. Also realize that the speed is not constant during the catch--you'll need to use the average speed.

 

[Jtappan]

ok i did it again and got .2722222 s for the time. just did xf-xi = .5(vf+vi)t

 

[Doc Al]

Don't forget to use distance in meters, not cm.

 

[Jtappan]

.002722222 is the time??

giving force as .00001469988?

 

[Doc Al]

.002722222 is the time??

Good.

giving force as .00001469988?

No. How did you get that?

 

[Jtappan]

f(deltaT) = mv-mvi

did i plug it in wrong?

 

[Jtappan]

never mind i got it thank you for your help