Geography 2144A/B : Effects of Tourism

a force P pulls on a crate of mass (m) that is in contact with arough surface. W represents the weight of the crate. FN representsthe normal force on the crate, and f represents the frictionalforce.

P= 160 N
f= 80 N
w= 196 N
60 degree angle

a) calculate the net force on the crate in the horizontalarea

B) what is the accerelation of the crate along the surface?

c)what is the normal force of the surface of the crate?

A steel wire in a piano has a length of 0.6000 m and a mass of5.100*10^-3 kg. To what tension must this wire be stretched inorder that the fundamental vibration correspond to middle C (fC =261.6 Hz on the chromatic musical scale)?

F=?, L=0.6000 m, m=5.100*10^-3 kg, n=0.50031N whereg=9.81m/s², f_c=261.6 Hz

I honestly can not figure out where to begin. I believe this isa standing waves problem so I'm almost positive that it should usethe following equation, but I can not figure out a properderivative or manipulation of the equation to find a seeminglycorrect answer.

f_n= (n/2L)*√(F/μ) where n=the number of harmonic(1,2,3...)