Purpose: To demonstrate Newton's First Law with an elevator moving at a constant velocity.

An "elevator" set up to raise a weight (the force probe) at a constant velocity. The force probe measures the tension on the string from gravity while the rotary motion sensor measures the position of the force probe as it moves up or down.

Use the file "Elevator.ds" in S:\Demonstration files\Mechanics. Just hit the start button to start lifting the force probe. Change the sign of the voltage to move it back down. Notice that the force measured stays the same despite the string pulling upward on it (except for perturbations caused by the vibrations in the string). Since there is no acceleration, the net force is 0 from the movement, so the force remains the same as its weight.

Setup Notes: The motor plugs into the power amplifier, and the amplifier into Analog channel B of the interface. Plug the force sensor into Analog channel A, and the RMS into Digital channels 1&2.

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