- #1
vworange
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1. A disk of radius 2.90 cm and mass 1 kg is pulled by a string wrapped around its circumference with a constant force of 0.46 Newtons. What is the angular velocity of the disk to three decimal places after it has been turned through 0.90 of a revolution?
So I've been using:
[tex]\alpha=\tau/I[/tex]
More specifically:
[tex]\alpha=(r*F)/(.5mr^2)[/tex]
I know I'm getting the acceleration just fine. I've then been using:
[tex]\omega^2 = 2\alpha\Delta\Theta[/tex]
I know the problem is coming in here. Probably in conversion of units (rad/s^2) to (rev/s^2) or something along those lines.
2. A large uniform "butcher block" rests on two supports and has a weight hanging from its end. The block has a mass of 100 kg and a length of 2 meters. If L = 1.50 meters and the hanging weight is 157 Newtons, what is the force on the left support to the nearest Newton?
The ball hangs on the right end of the block, the first support is on the left end of the block and the second support is 1.5 meters away from the left end of the block.
I've been trying all sorts of things, including:
L = 2.0 m
d = 1.5 m
F2 = mg(L/d)
F1 = mg - F2
I'm pretty sure the answer should be negative.. but i don't have it right yet.