Physics 11, kinetic energy problem

AI Thread Summary
The discussion revolves around solving a kinetic energy problem involving a tennis ball struck by a racquet. The average force exerted on the ball is 150.0 N, with a mass of 0.060 kg and a contact time of 0.030 s. Participants suggest using impulse to find the ball's velocity, leading to the calculation of momentum and ultimately kinetic energy. The correct kinetic energy calculated is 169 J, confirming the solution. Additional questions on related topics are posed, indicating a desire for further assistance.
Iceclover
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Hey if anyone could help me work through a couple of problems that would be great!:smile:

Homework Statement



It is not uncommon during the service of a professional tennis player for the racquet to exert an everage force of 150.0N on the ball. If the ball has a mass of 0.060kg and is in contact with the strings of the racquet for 0.030s what is the kinetic energy of the ball as it leaves the racquet? Assume the ball starts from rest


Homework Equations



Ek=1/2mv^2

The Attempt at a Solution


I'm not sure really where to start here...
 
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A hint: impulse.
 
Well, you know what you'll need to find Kinetic Energy--mass and velocity. You're given mass. Can you think of any other equations that might help you find velocity?
 
what do i do once I've figured that out?
 
d=vt but i don't have a distance either
 
Once you've figured what out?
 
oh my god i think i got it, will someone let me know if i got it right, just let me work it out.
 
There is no need to create so many posts. :wink:
 
i got 169J
 
  • #10
Looks OK to me, whose brain is fried!
 
Last edited:
  • #11
Iceclover said:
i got 169J

That's correct.
 
  • #12
p=Ft
p=150(0.030)
p=4.5

p=mv
4.5=(0.06)(v)
v=75m/s

Ek=1/2m^2
Ek=1/2(0.060)(75^2)
Ek=169J
 
  • #13
Ok i have a couple of other question so if anyone wants to stick around and help...?
 
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