PASCO CI-6461 Force Platform - Manual (Page 4)

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F o r c e P l a t f o r m Su g g e s te d A c ti v i t i e s
4
Suggested Activities
Hang Time
Stand on the platform and jump vertically. Look at a graph of force versus time to
determine your “hang time,” or how much time you spend in the air. Is you hang time
related to how high you jump? What other factor affect hang time?
For more precise time measurements, use a higher sampling rate.
Vertical Impulse
Use a motion sensor (CI-6742) to measure the position and velocity of the top your
head as you jump on the platform. What is your measured vertical velocity at the
moment your feet leave the platform? If you assume that you are a point mass, does
this velocity correspond with your measured hang time? Why not?
Stand on the platform and press the tare button. Bend your knees and jump with a one
smooth motion. The area under the force versus time plot is the impulse. How does
the impulse of jumping compare to the impulse of landing? Using the measured
impulse, calculate your launch velocity.
Compare the velocity measured by a motion sensor to the velocity calculated from the
impulse. Why are they not necessarily equal?
Horizontal Impulse
Hang the Force Platform on a wall. Press the tare button. Sit on a rolling chair, a
kinesthetics cart (SE-8747), or a hovercraft (ME-9838) and push off against the plat-
form. Measure the impulse, or the area under a plot of force versus time. How is the
impulse related to your momentum immediately after pushing off?
Use a motion sensor (CI-6742) to measure your velocity as you push off. Use this
velocity to calculate your momentum and compare it to the impulse. (Remember to
take into account the mass of the person and the chair, cart, or hovercraft.)
Force Distribution (With Two Platforms)
Place two Force Platforms on
the floor, and place two parallel
boards (as pictured) to act as a
bridge. Press the tare buttons.
Place a heavy ball on the
boards. Set up a motion sensor
(CI-6742) to measure the posi-
tion of the ball. While collecting
data, give the ball a push so that
it rolls along the boards.
What is the relationship between the position of the ball and the
force measured by each platform? How does the sum of the forces change?
Calculate the changing torques applied to the boards by each platform and the ball as
the ball rolls. How does the sum of the torques change?
Motion Sensor