- #1

BlasterV

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**Impulse and Momentum problem! HELP!**

Joe Varsity kicks a football of mass 1 kg. As his foot makes contact with the ball, it exerts a force which gradually increases to a maximum value over milliseconds, then falls immediately to zero, as shown in the graph above. The force is given by the equation

Force = (250 N) * (t / tsub0)^2

where tsub0 equals 1 millisecond.

What is the impulse given by Joe's foot to the ball? Don't forget the units!

I did this: Integral of 0 to .005 of ( 250 N * (t/tsub0)^2 ) dt

Evaluate from 0 to .005 of (( 250 N * (t/tsub0)^3) / 3 )

Impulse = (250N * ((.005/.001)^3) /3 ) = 10416.67 J

This is wrong :(

The ball was originally sitting on the tee, motionless. What is its speed immediately after Joe kicks it?

Without a correct impulse I can't even hope to do this.

But in terms of variables I don't know the equation to find this either :(