Help Needed: Solving Homework Equations Without Enough Variables

AI Thread Summary
The discussion revolves around two physics homework problems where the original poster feels there are insufficient variables to solve them. The first problem involves calculating the work done on a baseball thrown at 35 m/s, while the second concerns determining the force needed to stop a 2000lb car over 100ft. Participants suggest using the work-energy theorem to approach both problems, indicating that this method can provide the necessary relationships between variables. The original poster expresses confusion over missing information, particularly time and velocity. Overall, the conversation emphasizes the importance of applying the work-energy theorem to solve these types of physics problems effectively.
krash91
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Hey guys, I'd love some help with these problems, its seems to me that there aren't enough variables.

Homework Statement


A .145kg baseball leaves a pitcher's hand at a speed of 35 m/s. If air drag is negligible, how much work has the pitcher done on the ball by throwing it?


Homework Equations


W=FD


The Attempt at a Solution


W=(MA)(VT)

Seems like I can't solve it without the time it was in the air.

And this one as well

Homework Statement


Find the force needed for friction in the tires of a 2000lb car to stop it in 100ft

Homework Equations


W=FD?

The Attempt at a Solution


Again, it seems like there aren't enough varibles. If I had the velocity of the car then it would make sense.

Some hints and nudges in the right direction would be great!
 
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welcome to pf!

hey krash91! welcome to pf! :wink:

for both questions, use the work energy theorem …

what do you get? :smile:​
 

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