Gravitational forces simulation. The Physical Pendulum with Forces model displays the gravitational, normal, and friction forces acting on a mass attached to a pivoted rod. These forces cause the mass to accelerate in the radially and tangentially with respect to pivot. Although gravity is always downward, friction and normal force change direction in order to keep the mass in the same position on the stick.

Run the simulation and note how forces change magnitude and direction.Although gravity is always downward, friction and normal force change direction in order to keep the mass in the same position on the stick.
1. Derive expressions for the angle and angular velocity as a function of mass and R so that friction is zero at the top of the swing. Repeat for a centered rod.?Test your expression.
2. Derive expressions for the angle and angular velocity as a function of mass and R so that the normal force is zero when the rod is horizontal. Repeat for a centered rod. test your expression.

The Physical Pendulum Forces model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_mech_newton_PhysicalPendulumForces.jar file will run the program if Java is installed.

Requirements:
* Java

The license of this software is Freeware, you can free download and free use this graphing software.