Determining the time of a collision

[robertmatthew]

Homework Statement

A 473-gram baseball traveling at 37 m/s is hit directly back at the pitcher with a speed of 45 m/s. If the force of contact between the bat and the ball is 3800 Newtons, how long is the bat in contact with the ball?

Homework Equations

F= dp/dt

The Attempt at a Solution

F=dp/dt
t=dp/F
t=(m)(v₂-v¹)/F
t=(.473)(8)/(3800) ---> converted 473g into kg because Newtons are kg*m/s²
t=.000996 s

But that's not the right answer. I've also tried not converted g->kg and that doesn't work either, so obviously there's something else I'm doing wrong, but I just don't know what it is.

 

[Dick]

Homework Statement

A 473-gram baseball traveling at 37 m/s is hit directly back at the pitcher with a speed of 45 m/s. If the force of contact between the bat and the ball is 3800 Newtons, how long is the bat in contact with the ball?

Homework Equations

F= dp/dt

The Attempt at a Solution

F=dp/dt
t=dp/F
t=(m)(v₂-v¹)/F
t=(.473)(8)/(3800) ---> converted 473g into kg because Newtons are kg*m/s²
t=.000996 s

But that's not the right answer. I've also tried not converted g->kg and that doesn't work either, so obviously there's something else I'm doing wrong, but I just don't know what it is.

The difference in velocities between 37m/s towards the bat and 45m/s away from the bat is 82m/s. You have to consider the sign of the velocities.

 

[robertmatthew]

Wow, that completely went over my head... now I feel really stupid, haha. Thanks for pointing that out, sorry for the waste of a post.

 

[Dick]

Wow, that completely went over my head... now I feel really stupid, haha. Thanks for pointing that out, sorry for the waste of a post.

Don't feel sorry. That's what the forum is for. If you get it the post is hardly wasted.