by darksaber21 » Sun Feb 03, 2013 7:04 pm
For 55, we know that impulse is involved as there was contact for a length of time, and there was a change in velocity due to the force inflicted during that time. As such:
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Using your kinematic equations, you should obtain:
(velocity right before impact) [unparseable or potentially dangerous latex formula]
(velocity right before impact) [unparseable or potentially dangerous latex formula]
So, [unparseable or potentially dangerous latex formula]
Reason why Δv is higher is because the initial velocity is in the negative direction, and the force caused the velocity not only to slow down but to speed up in the opposite direction.
So, now we can determine the force:
[unparseable or potentially dangerous latex formula]
We are not done yet. What we found was the average force on the ball. When the ball strikes the floor, there are two forces at that point in time: the normal force and the force of gravity. The sum of these forces equal the average force that we found. At this point, you could just circle E as that is the only answer larger than 3.4, but I'm going to just show the set-up anyway.
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Edit: I'm adding this here in case anyone will become confused:
[unparseable or potentially dangerous latex formula]
We are solving for N, the normal force placed on the ball that actually caused it to change direction
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So:
[unparseable or potentially dangerous latex formula]
Last edited by
darksaber21 on Tue Feb 05, 2013 6:43 pm, edited 1 time in total.
Now I know the stakes, and I'm willing to show what I gots. I will see you all at state for the first and final time, so let's end the year with a bang! :)
MTHS - Class 5A, District VII, Region I