# If Kinetic friction is a constant can I accelerate forever?

1. Oct 3, 2009

### sameeralord

If a limiting friction of an object is 10N and the kinetic friction is 5 N.

If I apply a force of 20 N continuosly would I be accelerating with a 5 N force forever.

2. Oct 3, 2009

### tiny-tim

Hi sameeralord!

(limiting friction is the maximum value of static friction)

No … you would be accelerating with a 10 N force forever …

once the object has started moving, you can forget the static friction completely (and you can reduce the applied force).

So if you apply a force of 6 N continuously, you will be accelerating with a 1 N force forever.

3. Oct 3, 2009

### Staff: Mentor

You meant 15 N. Right?

4. Oct 3, 2009

Right!

5. Oct 3, 2009

### willem2

You do need more and more power to overcome friction. The heat produced will become a problem too.

6. Oct 3, 2009

### Archosaur

Now this is a "work" problem. Are you familiar with "work"?

Work is a measurement of energy, and is equal to force X distance.

In this case, 15N (the force of friction) times the distance the object slides = the heat energy given off (in "joules").

So, when the object is moving faster, it covers more distance per unit time, so it also generates more heat per unit time.