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# Problem 4.7: A ball constrained to move on a rod

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A 20-kg ball has a hole with a rod passing through. The rod exerts a force as needed that constrains the ball to move along the rod. An applied force is now added (the "pulling" force) so the ball is pulled as shown **(position is given in meters and time is given in seconds)**. The force vector is shown as a red arrow, and the force makes an angle θ with the horizontal. The velocity is given in meters/second. You may adjust the angle and/or the magnitude of the pulling force (*F* < 7 N). Restart.

- How does the acceleration change as you vary the pulling force for a constant angle?
- How does the acceleration change as you vary the angle for a constant pulling force?
- Combine your answers above to obtain a general mathematical formula for the acceleration of the ball due to an arbitrary applied force.
- Determine the general mathematical formula for the normal force the rod exerts on the ball when an arbitrary force is applied to the ball.

Script authored by Steve Mellema, Chuck Niederriter and modified by Mario Belloni.

Problem authored by Mario Belloni.

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