MechanicsBeginner

Laws of Collisions

Explore conservation of momentum and mechanical energy in elastic and inelastic collisions using two carts on a frictionless horizontal track.

Duration: 90 min

6 Topics

CollisionsConservation of MomentumKinetic EnergyElastic CollisionInelastic CollisionVelocity

Lab Details

Title: LAB 4. Laws of collisions.

Course: PHYS 151 LABS / MEDTECH PHYSICS LABS

Level: Freshman

Institution: SMU, MedTech

Learning Objectives

Verify momentum conservation in elastic and inelastic collisions
Compare measured post-collision velocities with theoretical formulas
Analyze graphical relationships between initial and final velocities
Compare measured and predicted collision ratios

Interactive Simulation

Lab Assessment

Complete the following questions based on your observations from the simulation.

Elastic Test: $m_1=m_2=1\,kg$ , $v_2=0$ , $v_1=20$

I.1Table filling

Run elastic test with specified values and fill the table.

Elastic Test: $m_1=m_2=1\,kg$ , $v_2=0$ , $v_1=20$

*(6 points)

Run elastic test with specified values and fill the table.

Record pre/post-collision values and calculated quantities.

Complete the table:

$m_1$ (kg)	$m_2$ (kg)	$v_1$ (m/s)	$v_2$ (m/s)	$v_1'$ (m/s)	$v_2'$ (m/s)

Elastic Test: $m_1 = 2m_2 = 2\,kg$ , $v_2 = 0$ , $v_1 = 20$

I.2Table filling

Run elastic test with second mass configuration and fill table.

Elastic Test: $m_1 = 2m_2 = 2\,kg$ , $v_2 = 0$ , $v_1 = 20$

*(6 points)

Run elastic test with second mass configuration and fill table.

Record complete dataset and compare with previous run.

Complete the table:

$m_1$ (kg)	$m_2$ (kg)	$v_1$ (m/s)	$v_2$ (m/s)	$v_1'$ (m/s)	$v_2'$ (m/s)

Elastic Formula Agreement

I.3Open-ended / Explanation & Calculation

Check whether measured post-collision velocities agree with equation (3).

Elastic Formula Agreement

*(6 points)

Check whether measured post-collision velocities agree with equation (3).

Show comparison and explain deviations if any.

Your Answer:

Head-on Elastic Case

I.4Open-ended / Calculation

For

m_1=m_2=1\,kg

v_2=-20\,m/s

v_1=20\,m/s

, determine post-collision outcome.

Head-on Elastic Case

*(5 points)

For

m_1=m_2=1\,kg

v_2=-20\,m/s

v_1=20\,m/s

, determine post-collision outcome.

Provide computed velocities and interpretation.

Your Answer:

Elastic Collision Deduction

I.5Open-ended / Deduction

State what can be deduced/confirmed from elastic collision experiments.

Elastic Collision Deduction

*(4 points)

State what can be deduced/confirmed from elastic collision experiments.

Summarize key conservation-law conclusions.

Your Answer:

Inelastic Test: $m_1=m_2=1\,kg$ , $v_2=0$ , $v_1=20$

II.1Table filling

Run inelastic test with first configuration and fill table.

Inelastic Test: $m_1=m_2=1\,kg$ , $v_2=0$ , $v_1=20$

*(6 points)

Run inelastic test with first configuration and fill table.

Record measured and computed values.

Complete the table:

$m_1$ (kg)	$m_2$ (kg)	$v_1$ (m/s)	$v_2$ (m/s)	$v'$ common (m/s)

Inelastic Test: $m_1 = 2m_2 = 2\,kg$ , $v_2 = 0$ , $v_1 = 20$

II.2Table filling

Run inelastic test with second configuration and fill table.

Inelastic Test: $m_1 = 2m_2 = 2\,kg$ , $v_2 = 0$ , $v_1 = 20$

*(6 points)

Run inelastic test with second configuration and fill table.

Record all observations and values.

Complete the table:

$m_1$ (kg)	$m_2$ (kg)	$v_1$ (m/s)	$v_2$ (m/s)	$v'$ common (m/s)

Inelastic Formula Agreement

II.3Open-ended / Explanation & Calculation

Check whether measured post-collision velocities agree with equation (4).

Inelastic Formula Agreement

*(6 points)

Check whether measured post-collision velocities agree with equation (4).

Provide quantitative and qualitative comparison.

Your Answer:

Head-on Inelastic Case

II.4Open-ended / Calculation

For

m_1=m_2=1\,kg

v_2=-10\,m/s

v_1=20\,m/s

, determine post-collision outcome.

Head-on Inelastic Case

*(5 points)

For

m_1=m_2=1\,kg

v_2=-10\,m/s

v_1=20\,m/s

, determine post-collision outcome.

Show calculations and discuss result.

Your Answer:

Inelastic Collision Deduction

II.5Open-ended / Deduction

State what can be deduced/confirmed from inelastic collision experiments.

Inelastic Collision Deduction

*(4 points)

State what can be deduced/confirmed from inelastic collision experiments.

Focus on momentum and kinetic energy behavior.

Your Answer:

Velocity Sweep Data Table

T8Table filling

Repeat for different

v_1

values and record corresponding

v_2'

Velocity Sweep Data Table

*(6 points)

Repeat for different

v_1

values and record corresponding

v_2'

Gather complete table of measured values.

Complete the table:

$v_1$ (m/s)	$v_2'$ (m/s)

Plot $v_1$ vs $v_2'$

T9Graphing / Open-ended

Plot

(X=v_1, Y=v_2')

points, add legend, and comment the graph.

Plot $v_1$ vs $v_2'$

*(6 points)

Plot

(X=v_1, Y=v_2')

points, add legend, and comment the graph.

Use data from T8 and describe trend.

Plot your data:

v_2'

versus

v_1

v_2'

(m/s)

Left click: add point • Wheel: zoom • Right drag: pan

x: -, y: -

v_1

(m/s)

Graphical Slope $C'$

T10Open-ended / Calculation

Find slope

C'

v_2'

versus

v_1

by graphical method.

Graphical Slope $C'$

*(5 points)

Find slope

C'

v_2'

versus

v_1

by graphical method.

Show construction/fit method and computed slope.

Plot your data:

Graphical Slope

C'

Left click: add point • Wheel: zoom • Right drag: pan

x: -, y: -

Direct Ratio C

T11Open-ended / Calculation

Calculate ratio C directly from measured m1 and m2.

Direct Ratio C

*(5 points)

Calculate ratio C directly from measured m1 and m2.

Provide formula and value.

Your Answer:

Compare C(mea) and C(pre)

T12Open-ended / Comparison

Compare measured and predicted ratios.

Compare C(mea) and C(pre)

*(5 points)

Compare measured and predicted ratios.

Discuss agreement and sources of error.

Your Answer:

Conclusion

ConclusionOpen-ended / Explanation

Summarize what is learned and discuss whether this is a complete study of collision laws.

Conclusion

*(8 points)

Summarize what is learned and discuss whether this is a complete study of collision laws.

Mention missing cases and explain.

Your Answer:

Lab Instructions

Explore the Interface

Familiarize yourself with the simulation controls and available parameters.

Experiment with Variables

Modify different parameters and observe how they affect the system behavior.

Record Observations

Take note of patterns, relationships, and any unexpected results.

Test Your Understanding

Try to predict outcomes before running experiments to test your comprehension.

Tips for Success

Start Simple

Begin with basic scenarios before exploring more complex situations.

Take Notes

Document your findings and any questions that arise during experimentation.

Repeat Experiments

Don't hesitate to repeat experiments with different parameters to verify results.

Ask Questions

Use unexpected results as learning opportunities to deepen your understanding.

Back to All Labs Complete Lab Evaluation

Laws of Collisions

Lab Details

Learning Objectives

Interactive Simulation

Lab Assessment

Elastic Test: m1=m2=1 kgm_1=m_2=1\,kgm1​=m2​=1kg, v2=0v_2=0v2​=0, v1=20v_1=20v1​=20

Elastic Test: m1=m2=1 kgm_1=m_2=1\,kgm1​=m2​=1kg, v2=0v_2=0v2​=0, v1=20v_1=20v1​=20

Elastic Test: m1=2m2=2 kgm_1 = 2m_2 = 2\,kgm1​=2m2​=2kg, v2=0v_2 = 0v2​=0, v1=20v_1 = 20v1​=20

Elastic Test: m1=2m2=2 kgm_1 = 2m_2 = 2\,kgm1​=2m2​=2kg, v2=0v_2 = 0v2​=0, v1=20v_1 = 20v1​=20

Elastic Formula Agreement

Elastic Formula Agreement

Head-on Elastic Case

Head-on Elastic Case

Elastic Collision Deduction

Elastic Collision Deduction

Inelastic Test: m1=m2=1 kgm_1=m_2=1\,kgm1​=m2​=1kg, v2=0v_2=0v2​=0, v1=20v_1=20v1​=20

Inelastic Test: m1=m2=1 kgm_1=m_2=1\,kgm1​=m2​=1kg, v2=0v_2=0v2​=0, v1=20v_1=20v1​=20

Inelastic Test: m1=2m2=2 kgm_1 = 2m_2 = 2\,kgm1​=2m2​=2kg, v2=0v_2 = 0v2​=0, v1=20v_1 = 20v1​=20

Inelastic Test: m1=2m2=2 kgm_1 = 2m_2 = 2\,kgm1​=2m2​=2kg, v2=0v_2 = 0v2​=0, v1=20v_1 = 20v1​=20

Inelastic Formula Agreement

Inelastic Formula Agreement

Head-on Inelastic Case

Head-on Inelastic Case

Inelastic Collision Deduction

Inelastic Collision Deduction

Velocity Sweep Data Table

Velocity Sweep Data Table

Plot v1v_1v1​ vs v2′v_2'v2′​

Plot v1v_1v1​ vs v2′v_2'v2′​

Graphical Slope C′C'C′

Graphical Slope C′C'C′

Direct Ratio C

Direct Ratio C

Compare C(mea) and C(pre)

Compare C(mea) and C(pre)

Conclusion

Conclusion

Lab Instructions

Explore the Interface

Experiment with Variables

Record Observations

Test Your Understanding

Tips for Success

Start Simple

Take Notes

Repeat Experiments

Ask Questions

Elastic Test: $m_1=m_2=1\,kg$ , $v_2=0$ , $v_1=20$

Elastic Test: $m_1=m_2=1\,kg$ , $v_2=0$ , $v_1=20$

Elastic Test: $m_1 = 2m_2 = 2\,kg$ , $v_2 = 0$ , $v_1 = 20$

Elastic Test: $m_1 = 2m_2 = 2\,kg$ , $v_2 = 0$ , $v_1 = 20$

Inelastic Test: $m_1=m_2=1\,kg$ , $v_2=0$ , $v_1=20$

Inelastic Test: $m_1=m_2=1\,kg$ , $v_2=0$ , $v_1=20$

Inelastic Test: $m_1 = 2m_2 = 2\,kg$ , $v_2 = 0$ , $v_1 = 20$

Inelastic Test: $m_1 = 2m_2 = 2\,kg$ , $v_2 = 0$ , $v_1 = 20$

Plot $v_1$ vs $v_2'$

Plot $v_1$ vs $v_2'$

Graphical Slope $C'$

Graphical Slope $C'$