# Kinematics of particles

1. Sep 15, 2009

### amiv4

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

The slotted arm OA forces the small pin to move in the fixed spiral guide defined by r=Kθ. Arm OA starts from rest at θ=π/4 and has a constant counterclockwise angular acceleration $$\ddot{theta}$$ =α. Determine the magnitude of the acceleration of the pin when θ=3π/4.

any help is appreciated.

3. The attempt at a solution

I have no clue where to start.

2. Sep 15, 2009

### nvn

Hi, amiv4. Start by reading your text book and studying the example problems. The PF rules state, you must list relevant equations yourself, and show your work; then someone might check your math.