How do you calculate the total momentum of a system that involves two objects? For example, how do you calculate the total momentum of two cars as they are about to collide?
What are the units?
What are some other collisions besides "head-to-head" collisions?
Find the mass of each cart and the "weight." Enter into Data Table 1 below.
Place two carts on the track.
Press the Start Button.
Collide the two carts.
Press the Stop Button.
Press to select the Smart Tool. Press F1 to autoscale if necessary.
Use the left or right arrow buttons to find the velocity of one of the carts just before and just after the collision. See the picture above.
Enter the values of the initial and final velocities in Data Table 2.
Press then the number "7" to create a new graph. Select "vel2" as in the picture above.
Use the left and right arrow buttons in conjunction with the Smart Tool to find the velocity of this cart just before and just after the collision.
Enter the values of the initial and final velocities in Data Table 2.
Press and "Graph 1" to return to the original graph.
Repeat the previous steps for a total of 20 collisions varying the velocities and masses of the carts.
Data Table 1
Mass of Cart 1 (kg)
Mass of Cart 2 (kg)
Mass of Each "Weight"
Data Table 2
Initial
Final
Collision #
Velocity 1
(m/s)
Velocity 2
(m/s)
Velocity 1
(m/s)
Velocity 2
(m/s)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Calculate the total initial momentum and total final momentum for each of the 20 collisions. Enter the values into the Analysis Table below.
Analysis Table
Collision #
Initial Momentum
(kg * m/s)
Final Momentum
(kg * m/s)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Using graph paper or a spread sheet, find the graph the values from the Analysis Table.
Determine the slope of your graph.
Write an equation that relates the initial momentum to the final momentum.
What is the physical meaning of the slope from your Graph?
What is the physical meaning of the vertical intercept from your Graph?
Discuss the momentum of two carts before a head-on collision. Compare to the momentum after the collision as they move away in opposite directions.
Discuss the initial and final momentum of a firecracker before and after it explodes.
In billiards, a cue ball strikes a stationary eight ball head on. If the eight ball is half the mass of the cue ball and if the cue ball becomes stationary immediately after the collision, what is the velocity of the eight ball immediately after the collision?
Button.
to select the Smart Tool. Press F1 to autoscale if necessary.
then the number "7" to create a new graph. Select "vel2" as in the picture above.
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