Trying to understand the relationship between Newtons, Joules and Work

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Discussion Overview

The discussion revolves around the relationship between force, energy, and motion, specifically focusing on the concepts of Newtons, Joules, and work. Participants explore how these quantities interact when a force is applied to a mass over a distance, examining implications for velocity and acceleration.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant questions whether a force of 1 Newton applied over 3 meters implies a specific acceleration for a 1 kg mass.
  • Another participant clarifies that 1 Newton times 3 meters equals 3 Joules, indicating that this is a measure of energy.
  • There is a suggestion that 3 Joules could be used to determine the velocity of the mass, although the exact relationship is not fully established.
  • A later reply states that 3 Joules of work was done on the mass and mentions that energy conservation can be used to find the kinetic energy, implying the speed will not be 1 m/s.
  • One participant points out a potential misunderstanding regarding the units of acceleration in the context of uniform acceleration.

Areas of Agreement / Disagreement

Participants express differing views on the implications of the energy calculated and how it relates to the velocity of the mass. There is no consensus on the specific outcomes or calculations involved.

Contextual Notes

Some assumptions about the conditions of motion, such as uniform acceleration, are not fully clarified. The discussion includes unresolved mathematical steps regarding the calculations of speed and acceleration.

phleaf
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A force of 1 Newton times 3 meters, can that mean : a 1 kg mass pushed over 3 meters went from 0 to 1 m /s/s ?
 
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1 Newton x 1 meter = 1 joule

A joule is a measurement of energy. In your case, 1 Newton x 3 meters is 3 joules of energy.

Since you know the energy is 3 joules, what can you conclude about the velocity of a 1kg mass being pushed 3 meters.
 
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3 joules were needed to change the velocity from 0 to 1 m/s ?
 
You did 3 Joules of work on the mass. Energy is conserved so you know what its kinetic energy is. You can calculate its speed from that... and it won’t be 1 m/sec.

Or you can calculate the acceleration (you know the force and the mass) and use the equation that relates distance, time, and acceleration to calculate the time it took for the mass to move 3 meters. Once you have the time you can calculate its speed... and it should agree with the other speed calculation.

This would be a really good time to Google for “SUVAT equations”
 
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phleaf said:
0 to 1 m /s/s ?
Something wrong with your units there, I'm afraid - if you intended to describe uniform acceleration.
 

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