Please help me with these three questions,they deal with coefficient of friction

1) A car rounds a turn of radius 25m at a speed of 20m/s. Find the coefficient of friction neccessary to keep the car on the road

2) A man is attempting to slide a piece of furniture weighing 750N long a floor. Ifhe exerts a force of 75N along a rope and angle of 35 degrees and the object does not move, what is the minimum value for te coeficient of friction?

3) Consider a block on a plane inclined at an angle of 30 degres. If the block weights 950N, what coefficient of friction is neccessary to hold it stationary?

Physics - bobpursley, Wednesday, January 27, 2010 at 8:00pm
1) set mv^2/r= mu*mg
solve for mu

2) the vertical component of tension reduces weight.

friciton= mu*(mg-75sin35)
horizontalforce= 75*cos35
set them equal, solve for mu.
3) I will be happy to critiqeu your thinking.

I wanted to know what you mean by the formulas. I do not know what the mg stands for...If it is miligrams then how does that relate to the problem. Thanks for your time again.

mg is mass*acceleration due to gravity.

Something is gravely wrong here? You must be lacking a text, or class instruction. mu (or the greek symbol for mu) is pretty standard. mg is pretty standard for weight.