Another physics question !!!!!

jenic

Well-known Member
Man i hate this subject soooooo much, i cant get AS so what look will i have if i carry on. Anyway this is a simple one, which formula links force, speed and power?
 

fortean

Active Member
Man i hate this subject soooooo much, i cant get AS so what look will i have if i carry on. Anyway this is a simple one, which formula links force, speed and power?

Is this what you're after...

force = mass x acceleration

It's just that force and power seem to be the same thing.
 

jenic

Well-known Member
Nope, i'll give you the question:

how much power must be generated to maintain a steady speed of 8m/s against resisting forces of 30N
 

fortean

Active Member
Nope, i'll give you the question:

how much power must be generated to maintain a steady speed of 8m/s against resisting forces of 30N

Well 1 Joule = 1 Newton Meter so you need 30 Joules to move it for 1 Meter.
 

brendan_dj

Active Member
30N of power is needed.

A body will continue travelling at a constant speed unless acted upon by another force.
 

fortean

Active Member
For every second you would move it 8 Meters so that means every second you use up 240 Joules or 240 Watts
 

Chox1988

Distinguished Member
For every second you would move it 8 Meters so that means every second you use up 240 Joules or 240 Watts

If you are being pushed with a force of 30N backwards, if you apply a force of 30N forwards you stay still, you wouldn't be at a speed of 1m/s, because the forces are equal. Forward force would have to be larger than the backward force to be moving forward.

Correct me if thats wrong but im still thinking about how to go about the answer.
 

fortean

Active Member
If you are being pushed with a force of 30N backwards, if you apply a force of 30N forwards you stay still, you wouldn't be at a speed of 1m/s, because the forces are equal. Forward force would have to be larger than the backward force to be moving forward.

Correct me if thats wrong but im still thinking about how to go about the answer.

That's if you were not moving to start with but if you are already moving then you just need to maintain the balance in the forces. Any inbalance will cause you to slow down or go faster.
 

Chox1988

Distinguished Member
That's if you were not moving to start with but if you are already moving then you just need to maintain the balance in the forces. Any inbalance will cause you to slow down or go faster.

yeh fair enough, i stand corrected.
 

brendan_dj

Active Member
If you are being pushed with a force of 30N backwards, if you apply a force of 30N forwards you stay still, you wouldn't be at a speed of 1m/s, because the forces are equal. Forward force would have to be larger than the backward force to be moving forward.

Correct me if thats wrong but im still thinking about how to go about the answer.

The question was regarding "maintaining a steady speed of.."
not "accelerate to 8m/s from stationary" So the only force required is the force needed to balance the 30N friction force working in the opposite direction.
 

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