- #1
Raios168
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Homework Statement
A billiard ball is imparted a horizontal impulse of 2 N*s at a height 4 cm above the center of the ball. The mass of the ball is 0.02 kg and it has radius 5 cm. Find velocity of the center of mass right after the impulse.
Note: I simplified the question, I was actually given that a linearly increasing force was applied from 0 to 40 000 N in 0.001 seconds and then was decreased linearly from 40 000 N to 0 in 0.001 seconds. So this created a triangle when I created a Force-time graph, calculating the area of the triangle yielded 2 N*s
2. Homework Equations
L = Iw
The Attempt at a Solution
Okay so the impulse causes more rotational motion than translational meaning Rw is greater than Vcm since it is hit above 2/3 its radius.This means friction (not sure if kinetic or static) will point opposite the direction of rotation. This makes sense since it will create a torque in the opposite direction of rotation causing rotation to decrease and translation to increase (will eventually start pure rolling). Alright so this means the impulse (2) simultaneously creates angular momentum and also linear momentum. With this I got:
2 = MVcm + Iw
I also have the net force equation:
F = Ma
f = Ma --> f is friction
μMg = Ma ----> I don't know μ so this doesn't get me anywhere
Then I looked at the torque about the center of mass of the ball:
∑τ = fR ----> I once again do not know μ so not helpful
Alright so this is where I've gotten. I have no clue where to go from here, could really use some assitance. Thanks in advance.