Java程序辅导

Projectile Motion (Virtual Lab)
Background
In this experiment, you will investigate what variables, if any, affect the motion of a projectile. Since the
equations of motion for a projectile are rather complicated, this investigation will be conducted virtually,
with the aid of a Java applet.
Mass of Projectile
1. Open the Projectile Motion applet.
2. Enter a velocity of 50.0 m/s and a launch angle of 45.0 degrees. These variables will remain constant
through the procedure.
3. Fire the projectile with the different masses listed in Table 1. Record the statistics of the motion in
each case.
4. Describe the shape of the path the projectile traces on the screen.
5. What affect does mass have on the motion of the projectile; i.e., which of the displayed statistics
changes? Why do you think this is the case?
6. Do you think the force applied to the different masses would also be the same? Explain your answer
using Newton’s laws of motion.
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7. What amount of time do you estimate for the projectile to reach its maximum height?
Initial Velocity of Projectile
1. Refresh the web page. Enter a mass of 5.0 kg and a launch angle of 45.0 degrees. These variables
will remain constant through the procedure.
2. Fire the projectile with the different velocities listed in Table 2 and record the statistics.
3. What affect does velocity have on the motion of the projectile?
4. How do the initial and end velocities of the projectile compare for each launch?
Launch Angle of the Projectile
1. Refresh the web page. Enter a mass of 5.0 kg and a velocity of 50.0 m/s. These variables will remain
constant through the procedure.
2. Fire the projectile with the different launch angles listed in Table 3 and record the statistics.
3. At what angle was the maximum range (horizontal distance) reached?
4. At what angle was the maximum elevation achieved?
5. At what angle was the greatest “hang” time achieved?
6. Compare the maximum range (horizontal distance) reached for these pairs of launch angles.
10◦ and 80◦
20◦ and 70◦
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7. What pattern is observed for these angles and their maximum ranges?
8. What is the sum of each set of paired angles?
9. Do you notice any other paired combinations in the data table that share the same maximum range?
List them.
10. A projectile is launched at an initial speed of 50 m/s with a horizontal angle of 76◦. Use the simulation
to answer these questions: What is its range? State another angle that will produce the same range.
11. Does the simulation verify your prediction?
12. What is the sum of the two angles that produce this range?
Air Resistance
1. Refresh the web page. Enter a mass of 5.0 kg. This is the only variable that remains constant in the
procedure.
2. Fire the projectile with the different velocities and launch angles listed in Table 4 (note that some are
these are with air resistance, while others are without). Record the statistics.
3. What seems to be the over-all effect of air resistance on these characteristics of projectile motion?
Answer with increase, decrease, or none.
Maximum range
Maximum height
Total time
End velocity
4. Air Resistance is also known as what force?
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Summary
State the major ideas you learned about projectile motion from this virtual lab investigation.
Data
Table 1: Varying Mass
Projectile Maximum Maximum End Total
Mass Range Elevation Velocity Time
[distance] [height]
(kg) (m) (m) (m/s) (s)
1
5
10
20
Table 2: Varying Initial Velocity
Initial Maximum Maximum End Total
Velocity Range Elevation Velocity Time
[distance] [height]
(m/s) (m) (m) (m/s) (s)
10
20
30
40
50
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Table 3: Varying Launch Angle
Launch Maximum Maximum End Total
Angle Range Elevation Velocity Time
[distance] [height]
(degrees) (m) (m) (m/s) (s)
10
20
30
40
45
50
60
70
80
90
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Table 4: Air Resistance
Air Initial Launch Maximum Maximum End Total
Resistance Velocity Angle Range Elevation Velocity Time
[distance] [height]
m/s (degrees) (m) (m) (m/s) (s)
Yes 30.0 35.0
No 30.0 35.0
Yes 30.0 65.0
No 30.0 65.0
Yes 60.0 35.0
No 60.0 35.0
Yes 60.0 65.0
No 60.0 65.0
Yes 60.0 90.0
No 60.0 90.0
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