PASCO ME-6950 PAScar with Mass - Manual (Page 4)

012-07361B PAScar with Mass
3
Purpose
In this lab, the PAScar will be used to investigate one dimensional accelerated motion.
The car will be launched over the floor using the built-in spring plunger. The car will
“decelerate” over the floor under the combined action of rolling friction and floor
slope. You will be able to establish whether or not the acceleration of the car is con-
stant. This will be done by initially assuming a constant acceleration and then by
examining the results to see if they are consistent with this assumption.
Theory
The car will be allowed to roll to a stop. The distance D covered and the total elapsed
time T from launch to stop will be measured and recorded. The average velocity over
this interval is given by:
v
av
=
If the acceleration of the car is constant as it rolls to a stop over the floor, then the
initial instantaneous velocity of the car at the final moment of launch is given by:
v
0
= 2v
av
=
And the value of the acceleration would be given by:
a = = = –
If the acceleration and v
o
are known, then the time t
1
required to cover the distance d
to some intermediate point (i.e. short of the final stopping point!) can be calculated by
applying the quadratic formula to:
d = v
0
t
1
+ 1/2at
1
2
Calculated values of t
1
will be compared with directly measured values. The extent to
which the calculated values agree with the directly measured values is an indication of
the constancy of the acceleration of the car.
Note your theoretical values in Table 1.1.
Experiment 1: Kinematics
(Average vs. Instantaneous Velocities)
Figure1.1
EQUIPMENT NEEDED:
– PAScar (ME-6950)
– Metric tape (SE-8712)
– Stopwatch (SE-8702)
v
t
0 – v
0
T
2D
T 2
D
T
2D
T
(EQN-1):
(EQN-2):
(EQN-3):
(EQN-4):