PASCO ME-6962 PAStrack Systems - Manual (Page 22)

®
P A S t r a c k S y s t e m s E x p e r i m e n t 7 : N e w t o n ’ s S e c o n d L a w
22
5. Pull the cart back until the mass hanger reaches the pulley. Record this initial
release position in Table 7.1. This will be the release position for all the trials.
Make a test run to determine how much mass is required on the mass hanger so
that the cart takes about 2 seconds to complete the run. Because of reaction time,
too short of a total time will cause too much error. However, if the cart moves too
slowly, friction causes too much error. Record the hanging mass in Table 7.1.
6. Place the cart against the end stop on the pulley end of the track and record the
final position of the cart in Table 7.1.
7. Pull the cart back to the initial release position. Release it and time how long it
takes to reach the end stop. Record the time in Table 7.1.
8. Measure the time at least 5 times with the same mass and record these values in
Table 7.1.
9. Add 500 g of mass to the cart and repeat the procedure.
Data Analysis
1. Calculate the average times and record them in Table 7.1.
2. Record the distance traveled (from initial to final position) in Table 7.1.
3. Calculate the accelerations and record them Table 7.2.
4. For each case, calculate (m
1
+ m
2
)a and record in Table 7.2.
5. For each case, calculate the net force, F
NET
, and record in Table 7.2.
6. For each case, calculate the percent difference between F
NET
and (m
1
+ m
2
)a and
record in Table 7.2.
Questions
1. Did the results of this experiment verify that F = ma?
2. Why must the mass in F = ma include the hanging mass as well as the mass of
the cart?
Table 7.1: Experimental Period
Initial release position = __________
Final position = __________
Distance traveled (
d
) = __________
Cart
Mass
Hanging
Mass
Time
Average
Time Trial 1 Trial 2 Trial 3 Trial 4 Trial 5
Table 7.2:
Cart Mass Acceleration
(m
1
+ m
2
)a F
NET
= m
2
g
% Difference