# Homework Help: Two Physics problems (angular velocity/acc) and Force by a stopper

1. Apr 3, 2012

### Kalookakoo

1. The problem statement, all variables and given/known data

1) The horizontal slot guide C moves downward at a constant velocity of 4.00 in/sec. Crank OP (radius rOP) is pinned at O and point P slides freely in horizontal slot guide. At the instant shown determine:
a) θ’ (The angular velocity of OP)
b) θ’’ (The angular acceleration of OP)
θ = 50.0º rOP = 8.00 in

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2) Collar C (weight w) is free to slide on the vertical steel rod (diameter d; length L). The collar is released from rest at a height of h above stopper A at the end of the rod. Determine the maximum force experienced by the rod.
w = 5.00 lbs d = 1/8 in
L = 2.00 ft h = 18.0 in
ESTEEL = 29000 ksi;

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3. The attempt at a solution

I don't even know where to start. My professor didn't put up the equation sheet and I didn't understand it when he did it in lecture earlier today. If someone could patiently help me through this I would appreciate it.

2. Apr 3, 2012

### Kalookakoo

Well I tried the fist one a bit and got:

(all taken from starting with y = 8cos(theta)
Angular velocity equal to -.6527 and angular acceleration to be -.35747.

The second one I believe I need a formula for, and have no idea.