# Forces and friction homework help please

1. Nov 15, 2007

### pyroknife

1. The problem statement, all variables and given/known data
A force of 50N is required to start a 10kg object moving from rest. What is the maximum value that (Ms) could be?
A)5
b).05
c).5
d).1
Any help would be greatly appreciated thanks.

2. Relevant equations

3. The attempt at a solution

2. Nov 15, 2007

### Dick

You'll have to start us out here. What's the normal force and what does the normal force have to do with static friction?

3. Nov 16, 2007

### pyroknife

Normal force is the force acting up on the object so the higher the normal force the less kinetic friction it takes to get the object moving. I cant find the normal force though.

4. Nov 16, 2007

### Dick

Exactly backwards. Frictional force is related to normal force times the Ms. So larger normal force means more friction. I think you might need to look in a book. How is the normal force related to weight? How is weight related to mass?

5. Nov 16, 2007

### pyroknife

I was trying to use this equation Ff=FnMs, but there are 2 unknowns so i cant solve for it

6. Nov 16, 2007

### pyroknife

I think the answer would be .5
Ff=FnMs
50=98Ms
Ms=.5(rounded)

7. Nov 16, 2007

### Dick

You've got it. Fn=mg by balancing the vertical forces.

8. Nov 16, 2007

Thank you