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Grade 11 · unit review

Review: Mechanical Energy and Collisions

Use energy and momentum models with explicit system boundaries.

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Bring the unit skills together

Use these 4 new cases to check your reasoning. Choices are temporary and are not saved to an account, sent to staff or recorded as school grades. Download your current review choices before leaving or reloading.

Unit review questions
1. Supplied case 5: mass (kg)=6; speed (m/s)=5, using the explicitly named quantities. Kinetic energy equals one-half mass in kilograms multiplied by speed in meters per second squared. What result follows?
Need a hint?
  • Kinetic energy equals one-half mass in kilograms multiplied by speed in meters per second squared.
  • Kinetic energy does not have a directional sign.
2. Supplied case 5: mass (kg)=4; height increase (m)=5, using the explicitly named quantities. Potential-energy increase equals mass in kilograms times model g of 10 meters per second squared times height increase in meters. What result follows?
Need a hint?
  • Potential-energy increase equals mass in kilograms times model g of 10 meters per second squared times height increase in meters.
  • The supplied g=10 is an approximation.
3. Supplied case 5: initial mechanical energy (J)=240; thermal transfer (J)=60, using the explicitly named quantities. Remaining mechanical energy equals initial mechanical energy minus thermal transfer. What result follows?
Need a hint?
  • Remaining mechanical energy equals initial mechanical energy minus thermal transfer.
  • Mechanical energy and total energy differ.
4. Which scientific label fits the specifically described step or feature? Supplied case: Isolated modeled bodies rebound without kinetic loss.
Need a hint?
  • Look for the described feature: momentum and kinetic energy conserved in model.
  • Compare the given mechanism with the other labels; do not infer unmentioned events.

The download contains your current choices and any checked feedback. Keep the separate transfer-task work in your own document; downloading its instructions does not mark it complete.

Use the skills in a new task

Create a four-panel explanation for “Mechanical Energy and Collisions” using one supplied case from each lesson. Include the observation, scientific mechanism or calculation, result and a limitation. You may draw and speak your explanation; all inputs are supplied.

Work on paper or in your own document. Explain the choices you made.

  • Use one supplied case from each of the four lessons.
  • Name the relevant structure, quantity or process in every panel.
  • Show calculations with units or a causal evidence chain.
  • Distinguish source facts from fictional classroom data.
  • State a model limit or a condition that would change the result.
Compare with a model response

Panel 1: Supplied case 1: mass (kg)=2; speed (m/s)=3, using the explicitly named quantities. Kinetic energy equals one-half mass in kilograms multiplied by speed in meters per second squared. What result follows? Result: 9 J. Reasoning: Substitute the supplied values: 0.5*(2)*(3)*(3) = 9 J. Square speed before multiplying. This formula concerns translational motion. Model limitation: only the stated classroom boundary and supplied observations are established; unmeasured real-world performance remains unverified. Panel 2: Supplied case 1: mass (kg)=2; height increase (m)=3, using the explicitly named quantities. Potential-energy increase equals mass in kilograms times model g of 10 meters per second squared times height increase in meters. What result follows? Result: 60 J. Reasoning: Substitute the supplied values: (2)*10*(3) = 60 J. Use a height change from a stated reference. Potential energy depends on system and reference. Model limitation: only the stated classroom boundary and supplied observations are established; unmeasured real-world performance remains unverified. Panel 3: Supplied case 1: initial mechanical energy (J)=100; thermal transfer (J)=20, using the explicitly named quantities. Remaining mechanical energy equals initial mechanical energy minus thermal transfer. What result follows? Result: 80 J. Reasoning: Substitute the supplied values: (100)-(20) = 80 J. Do not say transferred energy is destroyed. Use the supplied complete accounting boundary. Model limitation: only the stated classroom boundary and supplied observations are established; unmeasured real-world performance remains unverified. Panel 4: Two isolated carts collide elastically under the supplied model. What accounting applies? Which inference or prediction is best supported? Result: Combined momentum and kinetic energy are conserved in this ideal elastic model.. Reasoning: System conservation does not mean individual unchanged motion; internal forces can transfer quantities. Model limitation: only the stated classroom boundary and supplied observations are established; unmeasured real-world performance remains unverified.

A different response can also meet the criteria. Compare the evidence and reasoning, rather than copying the wording.