PASCO ME-6831 Ballistic Pendulum_Projectile Launcher - Manual (Page 58)

B a l l i s t i c P e n d u l u m / P r o j e c t i l e L a u n c h e r T e a c h e r ’ s G u i d e
®
54 012-05375C
Exp. 6: Conservation of Momentum in Two Dimensions
Setup
• If possible, use medium range setting instead of the short range setting. The medium range setting gives more
predictable results than the short-range setting.
Analysis
• Results for the x component of momentum should be within 5% of initial values. The total y component
should be very small compared to the x component.
Questions
1. Momentum is conserved on both axes.
2. Kinetic energy is nearly conserved in the elastic collision. There is some loss of energy which indicates that
the collision is not perfectly elastics.
3. Momentum is conserved for the inelastic collision, but kinetic energy is not conserved.
4. The angle should be nearly 90°. (Trials had angles of about 84°.)
5. In the inelastic case, the angle will be less than in the elastic case. The exact angle will depend on the degree
of inelasticity, which will depend on the type and amount of tape used.
Exp. 7: Vary the Angle to Maximize the Height
Procedure
1. You should be able to measure the angle of maximum height to within ±2%.
2. Measure the distance to the front edge of the ball.
3. Measure the initial height to the center of the ball.
Analysis
1. The initial speed should be close to the initial speed determined by other methods. You may wish to determine
the initial speed by the method in experiment 1, and use that value in your calculations for the rest of the
experiment.
2. Measured value and calculated vale should agree to within 3%.
Questions
1. The ball will have passed its peak by the time it reaches the wall. To show this, take the derivative of y with
respect to x:
y y
0
x

max
gx
2
2v
0
2  2
max
cos
-------------------------------- – tan + =
dy
dx
------

max
gx
2
v
0
2  2
max
cos
------------------------------- – tan =