PASCO ME-9215B Photogate Timer - Manual (Page 20)

16
Photogate Timer 012-06379B
®
h
Repeat the experiment several times, varying the mass of one or both gliders and varying the
initial velocity of glider
1
.
i
Try collisions in which the initial velocity of glider
2
is not zero. You may need to practice a
bit to coordinate the gliders so the collision takes place completely between the photogates.
Data and Calculations
c
For each time that you measured, calculate the corresponding glider velocity.
(e.g., v
1i
= ±L
1
/t
1i
, where the velocity is positive when the glider moves to the right and nega-
tive when it moves to the left.
d
Use your measured values to calculate p
i
and p
f
, the combined momentum of the gliders be-
fore and after the collision. Record your results in the table.
Questions
L
1
= L
2
=
Table 6.1 Data and Calculations
c
Was momentum conserved in each of your collisions? If not, try to explain any discrepancies.
d
If a glider collides with the end of the air track and rebounds, it will have nearly the same mo-
mentum it had before it collided, but in the opposite direction. Is momentum conserved in
such a collision? Explain.
e
Suppose the air track was tilted during the experiment. Would momentum be conserved in the
collision? Why or why not?
Optional Equipment
Design and conduct an experiment to investigate conservation of momentum in an inelastic
collision in which the two gliders, instead of bouncing off each other, stick together so that
they move off with identical final velocities. If you are using a PASCO airtrack, replace the
bumpers with the wax and needle. Otherwise, velcro fasteners can be used with most gliders.
m
1
m
2
t
1i
t
2i
t
1f
t
2f
v
1i
v
2i
v
1f
v
2f
p
i
p
f
(m
1
v
1i
+ m
2
v
2i
) (m
1
v
1f
+ m
2
v
2f
)