# Swinging Beam

1. Jul 29, 2016

### Doug Harvey

Can anyone help with calculating the starting and stopping torque required to rotate a uniformly laden beam with a total weight of 200kg around a fixed axis. The beam has a length of 2200mm and will be started from stationary, rotated through 70 degrees at which point it will stop and reverse. This motion to be repeated continuously. The total time to pass through 70 degrees is 4 seconds. Accelleration and de-celleration to be achieved in 0.5 second each. Looks similar to a cantilever jib crane.

2. Jul 29, 2016

### Simon Bridge

Certainly... it looks straight forward for boe calculation.
Start w a velocity-time diagram. You can find the top speed off that, and the average velocity for a single sweep.
This tells you the acceleration and thus the torque.

3. Jul 30, 2016

### Nidum

@Doug Harvey : As Simon suggests this is not a difficult problem to solve .

Are you familiar with torques , moments of inertia and angular accelerations ?