Physical interpretation of Force=power/velocity

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SUMMARY

The discussion centers on the physical interpretation of the equation Force = Power / Velocity. It clarifies that to maintain a constant force while velocity increases, power must also increase, contradicting the initial assumption that power decreases with increasing velocity. The relationship between force, mass, and acceleration is reinforced through Newton's second law, F = ma, indicating that constant force and mass yield constant acceleration. An example involving a glider illustrates the application of these principles in real-world scenarios, emphasizing the role of drag and potential energy.

PREREQUISITES
  • Understanding of Newton's laws of motion, particularly F = ma
  • Familiarity with the concepts of power, force, and velocity
  • Basic knowledge of energy transfer, specifically kinetic and potential energy
  • Experience with physics equations and their applications in mechanics
NEXT STEPS
  • Explore the relationship between power, force, and velocity in different physical systems
  • Study the implications of drag force on moving objects in a fluid
  • Investigate the concept of energy conservation in mechanical systems
  • Learn about the dynamics of gliders and their energy transformations during flight
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Students of physics, engineers, and anyone interested in understanding the dynamics of force, power, and motion in mechanical systems.

Generic Turtle
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I understand the derivation of the equation Force=power/velocity, but I'm not sure I quite understand the physical interpretation of this. If you had a constant force acting on a particle in a vacuum, then it would gain velocity and as it did so the power would have to go down for the force to be constant. Since the only transfer of energy is into kinetic energy as the particle is in a vacuum. If the power goes down this means the rate at which it gains kinetic energy decreases. This means its acceleration decreases but that doesn't make sense to me, why given a constant force is acceleration not constant. If you combine it with F=ma this implies that the mass of the particle has to increase for this to be the case. Am I intepreting all this correctly?
 
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The physical interpretation is that to apply a constant force and hence a constant acceleration, you must increase the power as the speed increases.

When you look at force=power/velocity and conclude that as velocity increases power must decrease to keep force constant, you have it backwards - to keep the value constant as the denominator of a fraction increases, you have to increase the numerator as well.
 
Nugatory said:
The physical interpretation is that to apply a constant force and hence a constant acceleration, you must increase the power as the speed increases.

When you look at force=power/velocity and conclude that as velocity increases power must decrease to keep force constant, you have it backwards - to keep the value constant as the denominator of a fraction increases, you have to increase the numerator as well.

Oh dear I feel super dumb now :O

Thank you though :)
 
When the force is constant, if the mass is constant too, the acceleration keeps a constant value, since F=ma...

An example of power, velocity and force with constant velocity/zero acceleration is in the case of a glider moving at constant velocity. The force of drag times velocity is the power of the glider; i.e. power=drag*airspeed... Of course, in this case, the energy of the glider comes from the variation of potential energy, as the glider loses altitude... Also, power=weight of the glider*vertical velocity... The drawing shows the forces and the speeds U,V, WW...
9643819798_5639ebe4e0_n.jpg
 

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