# Help with Statics

1. Feb 7, 2005

now on question 8 of my homework, and i am starting to wonder if i;ve been getting these question right. :yuck: It's to do with friction.

Relativally simple question: When an object is stationary, would the formula to find the resolved friction be: F = (mew, u) R or F (is less-than-or-equal-to) (mew, u) R?!
sorry bout the notation, have NO idea how to use it!

2. Feb 7, 2005

### here

friction

the normal force (force perpendicular to the plan of motion) is variable based on angle of incline or decline

3. Feb 7, 2005

thanks, but which formula applies to an object which is stationary, am i being stupid, co i swear our teacher told us one or the other?!

4. Feb 7, 2005

### here

you have static and kinetic frction the difference is that the constants are different, think about sliding a large object its hard to get it sliding, but you get it sliding its not as hard,

5. Feb 7, 2005

### Staff: Mentor

Static friction is always less than or equal to $\mu N$, where N is the normal force pressing the surfaces together.

6. Feb 7, 2005