Finding the Angle of Incline for a Block Sliding Down a Frictionless Surface

[cugirl]

Homework Statement

A block (starting from rest) with mass m = 4.5 kg slides down a frictionless incline a distance of d = 3m and then slides across a horizontal floor with friction (the coefficient of friction is Fk = 0.52). The speed of the block at the bottom of the incline is v1 = 7m/s. What is the angle of the incline? (Assume the acceleration was constant.)

Homework Equations

v initial = 0
mgsin(mu) - ƒk = ma

The Attempt at a Solution

I am wondering if I am approaching this correctly.
mgsin(theta) - ƒk = ma

 

[LowlyPion]

Homework Statement

A block (starting from rest) with mass m = 4.5 kg slides down a frictionless incline a distance of d = 3m and then slides across a horizontal floor with friction (the coefficient of friction is Fk = 0.52). The speed of the block at the bottom of the incline is v1 = 7m/s. What is the angle of the incline? (Assume the acceleration was constant.)

Homework Equations

v initial = 0
mgsin(mu) - ƒk = ma

The Attempt at a Solution

I am wondering if I am approaching this correctly.
mgsin(mu) - ƒk = ma

I hope you mean mgsinθ.

I would be concerned if you were trying to plug in μ, usually used for the coefficient of friction, as the angle.

 

[cugirl]

sorry -- that's what I meant. All the greek letters -- uggh.

 

[LowlyPion]

As to the problem, the equation you have doesn't address the basic acceleration down the incline, if your statement of the problem is correct in saying the incline is frictionless.