PASCO ME-6977 Fan Cart - Manual (Page 5)

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Model No.ME-6977 Demonstrations and Experiments
5
4. Attach the Sail to the Fan Cart by plugging the pegs of the sail into the holes at
the edge of the accessory tray on the cart. Attach the Sail so that its flat side faces
the fan.
5. Set the THRUST to VARIABLE, turn on the fan, and turn the VARIABLE
THRUST knob fully clockwise. Then, adjust the VARIABLE THRUST knob so
that the fan remains motionless. Turn the fan off after a short period of time.
6. Leave the thrust at the same setting, but remove the Sail and re-attach it so that its
curved side faces the fan.
7. Ask the students to predict which direction the cart will move with the sail
attached. Turn the fan on to show the direction of the cart’s motion.
Explanation: There is a force on the cart in one direction due to the fan pushing air
and there is another force on the cart in the opposite direction due to air hitting and
bouncing off of the sail. The bouncing air hitting the curved side of the sail causes
the force on the sail to be greater than the force of the air on the fan.
Suggested Experiments
Experiment #1:
Use a Motion Sensor or Tape Timer to measure the acceleration of the Fan Cart due to
a constant force. Add mass to the accessory tray of the cart and repeat. Determine the
relationship of acceleration to mass for a constant force.
Force
Air Flow
Equal
Force
Force
v
Air Flow
Greater
Force
NOTE: Many students will
expect the cart to not move.
However, the cart will have a
small acceleration opposite
to the acceleration without
the sail.