A 45- crate is placed on an inclined ramp. When the angle the ramp makes with the horizontal is increased to 30 , the crate begins to slide downward.

Q1:What is the coefficient of static friction between the crate and the ramp?
I got that answer and it was .58

It's the second I need help with;
Q2:At what angle does the crate begin to slide if its mass is doubled?

I don't even know where to start to find that.. any help greatly appreciated.

You need to find the angle where the component of the force due to gravity will equal the frictional force.

F_f = \mu R = 0.58(2mg cos\theta)

F_g = 2mg sin\theta

Equate those two, and solve for theta.

Post what you get :)

I set them equal to each other and got 30 degrees.
I plugged it into my online homework site and it was right!

Thank you so much!

You're welcome :)