1. Jan 17, 2013

### Macrobe

I have a question regarding Inertia. Exactly how much force, in Newtons, is required to overcome the inertia of exactly one kilogram of mass? It seems to me there must be some sort of quantity for it.

2. Jan 18, 2013

### VantagePoint72

It depends on how fast you want to accelerate the object. The equation is $\vec{F_{Net}} = m\vec{a}$, or in words, (net force acting on the object) = (mass of the object) x (acceleration of the object). This is Newton's second law. It takes, for example, 1 Newton of force to accelerate a 1kg object at 1m/s2.

3. Jan 18, 2013

### Macrobe

Ah. Okay...not exactly what I was looking for, but what I was looking for was probably wrong ;) thanks.

4. Jan 18, 2013

### VantagePoint72

Yes, if you were looking for some measure of a force required to overcome inertia that is independent of acceleration, then there's no such thing.

5. Jan 19, 2013

### BruceW

yeah, it is pretty counter-intuitive that f=ma, because in our everyday lives, most of the time there are frictional forces.

6. Jan 20, 2013

### Tik

I think Macrobe meant to ask how much force would be required to get a body off its stationary position. On a flat surface, it is equal to the co-efficient of static friction x Weight of the body (weight, not mass). If the body is on, say, a road, the force required to get the body would be around 0.7 times the weight of the body.