![[Under Construction]](../images/undercon.gif){kind=small}
Momentum
Exercise:
Problem:
For
most people it is common sense to realize that if a car and bicycle hit you,
traveling at the same speed, the car will do much more damage to you than the
bike. This is due to inertia.
Momentum is the measure of inertia in motion.
Therefore, momentum is influenced by the mass of an object and the
velocity it is traveling (momentum = mv). In
this lab you will be testing the theory of momentum.
Materials:
1.
Weights
2.
Ring
stand
3.
Test tube
holder
4.
String
5.
Block
6.
Meter
stick
Variables:
1)
Mass
2)
Velocity
– Hint: if everything falls at the same rate of acceleration due to gravity,
is it necessary to know what the velocity is?
Procedure:
1.
Setup the
experiment as shown in the picture above.
2.
Hang the
100g weight from the test tube holder and position the block so that it is
directly in front of the hanging weight.
3.
Raise the
weight to 5cm and release it so that it strikes the block directly.
a.
Repeat
the experiment 3 times
b.
Repeat
the step for the heights of 10cm & 20cm
c.
Repeat
steps a & b using 200g & 500g weights.
4.
Measure
the distance the block traveled and record on your chart.
5.
Calculate
and record the averages of the distances traveled.
6.
Graphing:
a.
Mass vs
distance (Triple Bar Graph)
i.
X – Height, Y – Distance
Data
Tables:
Weight
1: 100g
|
Height |
Trial
1 |
Trial
2 |
Trial
3 |
Average |
|
5cm |
|
|
|
|
|
10cm |
|
|
|
|
|
20cm |
|
|
|
|
Weight
2: 200g
|
Height |
Trial
1 |
Trial
2 |
Trial
3 |
Average |
|
5cm |
|
|
|
|
|
10cm |
|
|
|
|
|
20cm |
|
|
|
|
Weight
3: 500g
|
Height |
Trial
1 |
Trial
2 |
Trial
3 |
Average |
|
5cm |
|
|
|
|
|
10cm |
|
|
|
|
|
20cm |
|
|
|
|
Calculations:
1)
Calculate
the velocity for each of the heights. (Remember
that all the weights accelerate the same due to gravity.)
(d
= ½ g t2 or t2 = d / (0.5 * 980 cm/s2)
v = at
a.
(d=5cm)
b.
(d=10cm)
c.
(d=20cm)
2)
Calculate
the momentum for the different weights. (mass
* velocity) measured kg *cm/s or kg *m/s
|
Weight 1 |
@5cm |
|
@10cm |
|
@20cm |
|
|
Weight 2 |
@5cm |
|
@10cm |
|
@20cm |
|
|
Weight 3 |
@5cm |
|
@10cm |
|
@20cm |
|
Questions:
1)
Using the
results from the trials of 100g, predict the distances of the next to weights.
A)
Using the
above information, predict how far the block at weights 2 & 3 should have
traveled.
a.
(Wt2/Wt1)
x Dist@5cm for Wt1
_________cm
(Wt2/Wt1) x Dist@10cm for Wt1
_________cm
(Wt2/Wt1) x Dist@20cm for Wt1
_________cm
b.
(Wt3/Wt1)
x Dist@5cm for Wt1
_________cm
(Wt3/Wt1) x Dist@10cm for Wt1
_________cm
(Wt3/Wt1) x Dist@20cm for Wt1
_________cm
B)
Calculated
your percent error.
((predicted
– measured)/predicted) * 100%
a. Weight 2 @ 5cm
_________%
Weight
2 @ 10cm
_________%
Weight
2 @ 20cm
_________%
b. Weight 3 @ 5cm
_________%
Weight
3 @ 10cm
_________%
Weight
3 @ 20cm
_________%
2)
Name 3
conditions present that could have added to the error that you calculated.
a.
b.
c.
3)
Conclusion:
On your own paper.
a.
Discuss
the quality of your results. (State the accurate data that you were able to
measure?)
b.
What
conditions could have made your measurements inaccurate. (There are always
conditions that make measurements, setup, and the procedure inaccurate.)
c.
What
could have been done to improve the quality of your results?
(You can always improve.)