Comparing Kinetic Energy of Objects with Different Masses: A Simple Explanation

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SUMMARY

The discussion focuses on the comparison of kinetic energy between a 0.2 kg plastic card and a 20 kg lead cart, both subjected to equal forces over a distance of 1 meter. The kinetic energy formula, K.E. = (1/2)m*v^2, is utilized to analyze the situation. The conclusion drawn is that the kinetic energy of the two objects will differ due to their mass and resulting acceleration, despite the same force being applied. The work done on each object, calculated as Force multiplied by displacement, confirms that the lead cart will have greater kinetic energy due to its larger mass.

PREREQUISITES
  • Understanding of Newton's Second Law (F = m*a)
  • Familiarity with the kinetic energy formula (K.E. = (1/2)m*v^2)
  • Basic knowledge of work-energy principle (Work = Force x Displacement)
  • Concept of mass and acceleration in physics
NEXT STEPS
  • Study the relationship between force, mass, and acceleration in detail.
  • Explore the implications of the work-energy theorem in various contexts.
  • Investigate how different masses affect velocity and kinetic energy in real-world scenarios.
  • Learn about energy conservation principles in mechanical systems.
USEFUL FOR

Students studying physics, educators teaching mechanics, and anyone interested in understanding the principles of kinetic energy and motion dynamics.

feedmeister
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Hi all,

This really isn't a homework question, but rather a "coursework" question. It's pretty simple, I'm just trying to understand the concept. It's a workbook problem from my book.


Homework Statement


A 0.2 kg plastic card and a 20 kg lead cart both roll without friction on a horizontal surface. Equal forces are used to push both carts forward a distance of 1m, starting from rest. After traveling 1m, is the kinetic energy of the plastic cart greater than, less than, or equal to the kinetic energy of the lead cart? Explain.


Homework Equations


K.E. = (1/2)m*v^2
F = m*a

The Attempt at a Solution



I think it'd be the same because the velocities would make up for the difference in masses since there's the same amount of force.

If you can explain it to me I'd appreciate it. Thanks.
 
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Work done on a body = Force X displacement = Change in KE.
 
Ah, yes I forgot that equation. So I guess I was right.

Thanks!
 

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