Lab 6, Elastic Collision
Courtesy of Benli Young
Procedure 1, Prepare and weigh the gliders and all masses:
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Mass, Unit:( ) |
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Glider with tab |
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Glider with bumper |
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Masses |
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The length of glider should be the total length which the photo-gate can detect.
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Glider with tab |
Glider with bumper |
Average of two Gliders |
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Length, Unit:( ) |
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The positive velocities are measured to the right
Procedure 7, Make measurements:
For Case 1 and only for Case 1, print out one sample data, write down your sample calculation, and analyze it. See Sample 1.
| Case |
m1 (kg) |
m2 (kg) |
V1i (m/s) |
V2i (m/s) |
V1f (m/s) |
V2f (m/s) |
Pi (kg-m/s) |
Pf (kg-m/s) |
D P(kg-m/s) |
Ki (Joule) |
Kf (Joule) |
D K(Joule) |
(D K/ Ki ) ´ 100% |
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2 |
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3 |
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Procedure 7, a), Both gliders started by the launchers. See Sample 4.
| Case |
m1 (kg) |
m2 (kg) |
V1i (m/s) |
V2i (m/s) |
V1f (m/s) |
V2f (m/s) |
Pi (kg-m/s) |
Pf (kg-m/s) |
D P(kg-m/s) |
Ki (Joule) |
Kf (Joule) |
D K(Joule) |
(D K/ Ki ) ´ 100% |
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4 |
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Procedure 8, Answer the following two questions.
Q8-1: Answer the 2nd question on page 39.
“How well is the kinetic energy conserved in the collisions?”
Requirement:
Read the physics argument on Page 37 and write down your theoretical prediction. (0.5 points)
According to your two data tables, how might the type of collisions effect your percentage energy loss, i.e. (D K/ Ki )´ 100% values? Or, does it just not matter? (0.5 points.)
AQ8-2: Do the following question from Lab 5. i.e. Additional Question 10-2 for Lab 5: (Your theoretical work, 0.5 points; your final answer, 0.5 points.)
Consider m k is the coefficient of kinetic friction between the glider and the track. The track is unlike the practice question, perfectly leveled. Since now friction is the only force along the track, we can apply the 2nd law to determine the acceleration m kmg=fk=m|a|. You can still measure t1, t2, and L. In addition, we also need to measure the distance between the photo-gate and the deflecting bar, say D.
How can you figure out D p in terms of m, t1, t2, L, D, and m k?
Please recall that v1 and v2 are the velocities right before and after the collision. L is the glider length.
Use the formulas to analyze your data:
V1i , V2i : velocity before collision
V1f , V2f : velocity after collision
Pi = m1V1i +m2V2i , Pf = m1V1f +m2V2f , D P = Pi -Pf
“MKS” means “meter”, “kilogram”, and “second.” Hence, the SI unit of energy is exactly kg-m2/sec2. We call it “Joule.”
“CGS” means “cm”, “gram”, and “second.” Therefore, the CGS unit of energy would have to be g-cm2/sec2. People use to call it “Erg.”
Sample 1, m1 @ m2, V1i ¹ 0.000(m/sec), V2i = 0.000(m/sec)
| DATA TABLE - "collision Timer" Mode |
Special option values - "collision Timer" Mode |
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Row |
Times displayed by gate |
Row |
velocity |
velocity |
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# |
gate 1 |
gate 2 |
# |
(m/sec) |
(m/sec) |
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1 |
0.1898 |
0.1965 |
1 |
0.7324 |
0.7075 |
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statistics: |
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#: |
1 |
1 |
#: |
1 |
1 |
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Mean: |
0.1898 |
0.1965 |
Mean: |
0.7324 |
0.7075 |
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sd: |
0.0000 |
0.0000 |
sd: |
0.0000 |
0.0000 |
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sdom: |
0.0000 |
0.0000 |
sdom: |
0.0000 |
0.0000 |
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min: |
0.1898 |
0.1965 |
min: |
0.7324 |
0.7075 |
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max: |
0.1898 |
0.1965 |
max: |
0.7324 |
0.7075 |
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Sample 1 |
m1 (kg) |
m2 (kg) |
V1i (m/s) |
V2i (m/s) |
V1f (m/s) |
V2f (m/s) |
Pi (kg-m/s) |
Pf (kg-m/s) |
D P(kg-m/s) |
Ki (Joule) |
Kf (Joule) |
D K(Joule) |
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.20797 |
.20386 |
0.732 |
0.000 |
0.000 |
0.708 |
0.152 |
0.144 |
0.008 |
.0557 |
.0511 |
.0046 |
Sample 2, m1 > m2, V1i ¹ 0.000(m/sec), V2i = 0.000(m/sec)
| DATA TABLE - "collision Timer" Mode |
Special option values - "collision Timer" Mode |
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Row |
Times displayed by gate |
Row |
velocity |
velocity |
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# |
gate 1 |
gate 2 |
# |
(m/sec) |
(m/sec) |
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1 |
0.2322 |
0.2010 |
1 |
0.5987 |
0.6917 |
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2 |
0.0000 |
1.0595 |
2 |
Error |
0.1312 |
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statistics: |
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#: |
1 |
2 |
#: |
2 |
2 |
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Mean: |
0.2322 |
0.6302 |
Mean: |
Error |
0.4114 |
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sd: |
0.0000 |
0.6071 |
sd: |
Error |
0.3963 |
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sdom: |
0.0000 |
0.4293 |
sdom: |
Error |
0.2802 |
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min: |
0.2322 |
0.2010 |
min: |
0.5987 |
0.1312 |
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max: |
0.2322 |
1.0590 |
max: |
Error |
0.6917 |
m1 = 0.30824(kg), m2 = 0.20386(kg)
|V1i| = 0.599(m/sec), |V2i| = 0.000(m/sec)
|V1f| = 0.131(m/sec), |V2f| = 0.692(m/sec)
Sample 3, m1 <m2,V1i ¹ 0.000(m/sec), V2i = 0.000(m/sec)
| DATA TABLE - "collision Timer" Mode |
Special option values - "collision Timer" Mode |
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Row |
Times displayed by gate |
Row |
velocity |
velocity |
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# |
gate 1 |
gate 2 |
# |
(m/sec) |
(m/sec) |
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1 |
0.1942 |
0.2492 |
1 |
0.7158 |
0.5577 |
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2 |
1.1982 |
0.0000 |
2 |
0.1160 |
Error |
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statistics: |
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#: |
2 |
1 |
#: |
2 |
2 |
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Mean: |
0.2322 |
0.2492 |
Mean: |
0.4159 |
Error |
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sd: |
0.7099 |
0.0000 |
sd: |
0.4241 |
Error |
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sdom: |
0.5020 |
0.0000 |
sdom: |
0.2999 |
Error |
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min: |
0.1942 |
0.2492 |
min: |
0.1160 |
0.5577 |
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max: |
1.1982 |
0.2492 |
max: |
0.7158 |
Error |
m1 = 0.20797(kg), m2 = 0.30413(kg)
|V1i| = 0.716(m/sec), |V2i| = 0.000(m/sec)
|V1f| = 0.116(m/sec), |V2f| = 0.558(m/sec)
Sample 4, m1 @ m2, V1i ¹ 0.000(m/sec), V2i ¹ 0.000(m/sec)
| DATA TABLE - "Collision Timer" Mode |
Special option values - "Collision Timer" Mode |
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Row |
Times displayed by gate |
Row |
velocity |
velocity |
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# |
gate 1 |
gate 2 |
# |
(m/sec) |
(m/sec) |
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1 |
0.3650 |
0.3811 |
1 |
0.3835 |
0.3674 |
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2 |
0.4087 |
0.3903 |
2 |
0.3426 |
0.3688 |
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statistics: |
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#: |
2 |
2 |
#: |
2 |
2 |
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Mean: |
0.3869 |
0.3857 |
Mean: |
0.3630 |
0.3630 |
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sd: |
0.0308 |
0.0000 |
sd: |
0.02695 |
0.006135 |
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sdom: |
0.0218 |
0.0000 |
sdom: |
0.02048 |
0.004331 |
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min: |
0.3650 |
0.3811 |
min: |
0.3426 |
0.3688 |
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max: |
0.4087 |
0.3903 |
max: |
0.3835 |
0.3674 |
m1 = 0.302(kg), m2 = 0.303(kg)
|V1i| = 0.384(m/sec), |V2i| = 0.367(m/sec)
|V1f| = 0.343(m/sec), |V2f| = 0.369(m/sec)