# excerpt of PT school, in GIF

Question:
A force of 127 N is applied to a lever at a distance of 0.76 m from the right side of fulcrum. The force is applied at an angle of -93 degrees (below the horizontal) from the right horizontal and is pointing toward the fulcrum. The lever itself is 1.75 m long with a symmetrical density and has a mass of 5 kg. The fulcrum is positioned at the left edge of the lever. An additional weight of 225 N is applied on the right side of the lever at 47% of the lever arm length from the fulcrum on top of the lever, over a period of 20 minutes.

1. Where is the combined center of mass location along the horizontal axis of the lever and the additional weight (External forces)?
2. What type of lever system is described in this scenario (All torques that occur as a result of gravity should be considered external; the applied force should be considered internal)?
3. What is the calculated mechanical efficiency of the system (All torques that occur as a result of gravity should be considered external; the applied force should be considered internal)?
4. What is the rotational and translational force component of the applied force?
5. What is the net torque in this situation? Does the lever move up or does it move down?

Please excuse me while I assume the prone position.

## 3 thoughts on “excerpt of PT school, in GIF”

1. The prone position was one of my favorite intensive-study positions.

• Then, whilst in prone position, I think of how the interspinous space of L4-L5 is approximately the mid-horizontal point between the iliac crests. Palpation instructions are haunting me.

2. Scott says:

:) You have my deepest sympathy, Ms. Hannah.