Average Net Force: Kinetic Energy & Momentum

[Maiia]

This is just a general question- Given a beginning and ending velocity, and distance that the object travels, would the average net force be the change in kinetic energy divided by the distance? (Using energy methods only)
I think I've also seen avg force calculated with momentum...

 

[borgwal]

There are (at least) two sorts of average you can take:

If you want to calculate a force averaged over *distance*, you can use the change in kinetic energy, divided by distance: Work =\delta E=F_average * d

If you want to calculate an average over *time*, then that would be given by the change in momentum, divided by the total time: impulse=\delta P= F_average * T

 

[Maiia]

so Kef-Kei/d right?

 

[borgwal]

Yeah.

 

[Maiia]

ah i see- "average" is really misleading b/c u don't add the two numbers..
thanks!