PASCO SE-8747 Kinesthetics Cart KINESTHESIA-1 - Manual (Page 15)

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012-05787C Kinesthetics Cart
Experiment 6b: Independence of the
X and Y Motion of a Projectile
Now the cart and rider are given a constant velocity in the x-direction. Again the student rider
triggers the projectile launcher. Where will the ball land now? The same spot as for the motionless
cart, in front of the cart, or behind the cart? What is the relationship between the x and y motion?
Please make sure to instruct the rider not to launch the ball prematurely, i.e. while the
cart is given its initial push. The ball should be launched after cart and rider have reached a
constant speed.
Fig. 6-3: A student moving at constant speed launches a small, fluorescent ball vertically. The
student moving with the launcher sees the ball rise and fall vertically. Other students in the class
room describe the motion of the ball as parabolic.
Kinesthesia-1 affords a student the unique opportunity to ride along with the launcher (e.g.
Fig. 6-3). The student riding on the cart sees the ball rise and fall vertically and concludes that the
ball must have the same x-velocity as the cart. The remaining students in the classroom see the
fluorescent ball describe a parabolic trajectory. The relationship between the x and y motion is
parabolic due to the constant gravitational force in the y-direction and the constant velocity in the
x-direction.
It is also possible to mount a video camera on the Kinesthetic Cart and display the purely
vertical motion of the ball on a large video screen (uniformly moving frame). A second video
camera, stationary in the classroom, records the parabolic motion of the ball (laboratory frame).
That the motion is indeed parabolic can be verified using Video Analysis tools.