## pathosdebater 2 years ago Please help! :) Two objects have different weights. The first is three times as heavy as the second. If the objects are placed on the same surface, AND if the friction is different, how much different? a) One has three times greater friction b) One has nine times greater friction c) Friction of the two objects will always be the same

1. chemENGINEER

Well we denote friction force as fstatic=(mu)Fnormal where mu is the coef. of static friction. From the fact that Fnormal=mass*g....... what do you think?

2. chemENGINEER

mu will be the same in both cases, because they are on the same surface....

3. pathosdebater

So surface is the deciding factor in determining the friction of an object? So the friction would be the same since they are both on the same surface.

4. chemENGINEER

No. The surface will tell us the coefficient of friction (static or kinetic). As i said, frictional force=(mu)Fn............so if mu will stay the same then Fn must be what changes. and we know that Fn= mass*g..... and g stays the same bc we are on earth.... so thus frictional force=(mu)mass*g..... thus the difference will be a actor of the objects' masses

5. chemENGINEER

factor*

6. chemENGINEER

so the anwer would be a)

7. pathosdebater

Oh, okay. It's clearer now. Thanks.