Does greater acceleration result in more work done?

Click For Summary

Discussion Overview

The discussion revolves around the relationship between acceleration and work done when moving an object. Participants explore the implications of changing acceleration while keeping other variables constant, such as force and distance. The conversation touches on concepts from physics, including work, force, and kinetic energy, and examines different scenarios involving these variables.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant states that work done is calculated as W = Fs and questions whether doubling acceleration results in doubling work done.
  • Another participant argues that to achieve double the acceleration, one must also double the force, implying that work cannot simply be doubled by changing acceleration alone.
  • A participant provides an example calculating work done with a specific force and distance, emphasizing that work remains constant if force is unchanged despite changes in mass and acceleration.
  • Participants discuss specific scenarios involving a 1 kg body and different accelerations, calculating work done and kinetic energy gained in each case.
  • One participant notes that the assumption of starting and ending at rest affects the calculation of work done, particularly in scenarios involving gravitational potential energy.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between acceleration and work done, with some asserting that work is dependent on force and distance, while others explore the implications of changing acceleration. No consensus is reached on whether greater acceleration directly leads to more work done under all conditions.

Contextual Notes

Participants highlight the importance of clarifying changes made to force, mass, and distance, as well as the initial and final states of the object, which may affect the calculations and interpretations of work and energy.

Who May Find This Useful

This discussion may be useful for students and enthusiasts of physics, particularly those interested in the concepts of work, force, and energy in mechanics.

Imperial Sky
Messages
4
Reaction score
0
Work W done by moving the object with force F for distance s is W = Fs.
When I move the same object the same distance but with twice the acceleration, does
the work done gets also doubled?
By F=ma, doubling the acceleration yields m*2*a = 2F -> 2Fs = 2W.

I've mostly read, that if I want to increase work, I must either increase the mass of the object or
the distance, which gets me confused, because acceleration is also in the equation.
 
Physics news on Phys.org
I think your problem is saying that the same force can cause different acceleration.
As you say, F=ma, so to get double the acceleration you need twice the force.
Imperial Sky said:
I've mostly read, that if I want to increase work, I must either increase the mass of the object or
the distance, which gets me confused, because acceleration is also in the equation.
Well I wouldn't agree with that. Your original definition is the right one W=Fs so to increase work you must increase the force or the distance through which it moves.

Say you push a 5 kg mass with a force of 10 N over a distance of 3 m, then your work is 30 J.
If you treble the mass to 15 kg, but keep the force to 10 N, then over 3 m you still do 30 J of work.
The difference is that now the acceleration will be less and it will take you longer (time) to move through those 3 m.

You have to be clear about what changes you are making and ensure the changes you make are possible.
For example, you can't change acceleration but keep both force and mass the same, because F=ma. You can't change work if you keep both force and distance the same, because W=Fs.
 
If I move a 1kg body with an acceleration of 1 m/s^2 (F = ma = 1N) for 1 meter, I do 1J work.
If I move the same 1kg body the same 1 meter distance, but with acceleration 2 m/s^2 (F=2N), does that mean that I did 2 times more work (2J) than before?
 
Yes.
W = Fs = 2N x 1m = 2 J
 
Imperial Sky said:
If I move a 1kg body with an acceleration of 1 m/s^2 (F = ma = 1N) for 1 meter, I do 1J work.
If I move the same 1kg body the same 1 meter distance, but with acceleration 2 m/s^2 (F=2N), does that mean that I did 2 times more work (2J) than before?
How much kinetic energy will the object gain in either scenario, if it starts from rest?
 
In the first case, the work done is 1 J so it gains 1 J of KE if there is no friction etc.
In the second case, the work done is 2 J so it gains 2 J of KE if there is no friction etc.

You can check with your equations of motion:
1)## a= 1 m/sec^2 \ \ \ ⇒ v^2=2as = 2 \times 1 \times 1 = 2 m^2/sec^2 \ \ so \ \ KE = \frac {mv^2}{2} = \frac {1\times 2}{2} =1 J ##
2)## a= 2 m/sec^2 \ \ \ ⇒ v^2=2as = 2 \times 2 \times 1 = 4 m^2/sec^2 \ \ so \ \ KE = \frac {mv^2}{2} = \frac {1\times 4}{2} =2 J ##
 
Imperial Sky said:
I've mostly read, that if I want to increase work, I must either increase the mass of the object or
the distance
That's assuming that the object starts at rest and ends at rest, as if for example we're lifting it off the floor and setting it on a table. The work done is ##mgh##, and ##g## is constant so to increase the work done we need either a heavier object or a higher table.

If the object is moving at a different speed when we're done, we also have to allow for the work done to change its kinetic energy. In your problem, the greater force over the same distance means a greater final speed and hence greater kinetic energy.
 
  • Like
Likes   Reactions: FactChecker

Similar threads

  • · Replies 7 ·
Replies
7
Views
1K
  • · Replies 48 ·
2
Replies
48
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 46 ·
2
Replies
46
Views
3K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 7 ·
Replies
7
Views
986
  • · Replies 24 ·
Replies
24
Views
4K
  • · Replies 16 ·
Replies
16
Views
3K
  • · Replies 4 ·
Replies
4
Views
2K