Why Does Kinetic Energy Depend on Both Mass and Velocity?

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Discussion Overview

The discussion revolves around the dependence of kinetic energy on both mass and velocity, exploring intuitive explanations alongside mathematical derivations. Participants seek to understand the relationship between these variables in the context of physics.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant requests an intuitive explanation for the mathematical proof that kinetic energy depends on both mass and velocity.
  • Another participant argues that the intuitive understanding is inherently contained within the mathematical derivation of kinetic energy as mv²/2.
  • A participant discusses the role of force in determining speed and kinetic energy, noting that acceleration is dependent on the applied force and inversely related to mass.
  • Another participant provides intuitive examples, suggesting that the pain from dropping a brick versus a sponge illustrates the mass's contribution to energy, while the comparison of a bullet versus a foot emphasizes the role of velocity.

Areas of Agreement / Disagreement

Participants express differing views on the necessity of intuitive explanations versus mathematical derivations. There is no consensus on the best way to understand the relationship between mass, velocity, and kinetic energy, indicating ongoing debate.

Contextual Notes

Some arguments rely on assumptions about force, acceleration, and the nature of work done, which may not be universally accepted or fully explored in the discussion.

Bashyboy
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Hello,

I just read an article using math to prove that kinetic energy does indeed depend on both mass and velocity. But I was wondering if there was an intuitive explanation to accompany this mathematical one?
 
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Bashyboy said:
Hello,

I just read an article using math to prove that kinetic energy does indeed depend on both mass and velocity. But I was wondering if there was an intuitive explanation to accompany this mathematical one?

Why do you need the intuitive explanation ? Its itself contained in mathematical derivation.

Let a body be moving with initial velocity "v" be brought to rest by applying a certain force. Then displacement in the body while constant force is being applied on it is : 0 = v2-2as or s=v2/2a

But force applied on it is given by : F=ma

And Work done = Fs = mav2/2a
Work done : mv2/2
So kinetic energy of body is
mv2/2

Now intuitively , kinetic energy means energy of a body by virtue of its motion. Word kinetic itself means motion. Now body can only be in motion when it has a certain velocity (or momentum).Hence kinetic energy of a body depends on its velocity. Also kinetic energy can only be possessed when the work is being done on it (or in fact when it do work). But there could be no work done in absence of force. So kinetic energy depends on force. But without mass , force has no meaning. So in fact kinetic energy depends on mass also.
 
i think that the force by which an object is accelerated determines its speed apart from its mass.
as acceleration is directly dependent on the force applied.

for ex- if an object of less mass is pushed with a force of 10N and a heavier object with a force of 15N then the heavier one will have more kinetic energy.

but mass of the object opposes this explanation as acceleration is inversely dependent on mass and if mass is there then only the force exists
 
intuitive explanation...

Dropping a brick on your foot hurts more than a bath sponge -> Energy is proportional to mass.

Shooting yourself in the foot hurts more than dropping a bullet on your foot - > Energy is proportional to velocity.
 

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