PASCO ME-6964 PAStrack Wheel Set - Manual (Page 6)

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P A S t r a c k w i t h w h e e l s S u g g e s t e d A c t i v i t i e s
6
Activity 3: Fan Cart
Use this demonstration to compare the behavior of the fan cart to that of the motor-
ized cart in the previous activities. Before starting the fan cart each time, predict how
the fan cart and PAStrack with wheels will move relative to the stationary track and to
each other.
1. Place the PAStrack with wheels on a level stationary track.
2. Place a fan cart on the PAStrack with wheels. Turn on the fan. 2 What happens?
3. Attach a sail to the PAStrack with wheels so the air from the fan blows onto the
sail.
3 Now what happens?
Activity 4: The Slingshot Effect
In an elastic collision between a moving object and a much more massive stationary
object (a tennis ball bouncing off a wall, for instance), the speed of the smaller object
after the collision is equal to its speed before. The interaction that occurs when a
space probe “slingshots” around a planet can be thought of as a similar elastic colli-
sion. How do engineers use this technique to increase the speed of a space probe?
(Hint: consider the interaction in the planet’s frame of reference and in the Earth’s
frame of reference.)
In this experiment, you will observe an elastic collision between a “planet” (the PAS-
track with wheels) and a “space probe” (a freely moving cart).
Setup
1. Turn a dynamics cart upside down and use a rubber band secure it at one end of
the PAStrack with wheels, with the magnet-equipped end of the cart pointing
toward the center. This cart will be the bumper that the other cart collides with.
2. Place the PAStrack with wheels on a 2.2 m dynamics track, on a long tabletop, or
on the floor.
3. Position a motorized cart, as pictured, to push the PAStrack with wheels.
4. Place the other dynamics cart right-side up on the PAStrack with wheels with the
magnet end pointing toward the upside-down cart.
2 If you have a Time
Pulse Accessory, use it to
make the fan run for a
second or two before
stopping.
3 The picture shows the
sail included with Fan
Cart model ME-9485
attached with a binder
clip. You can also use a
piece of cardboard.