A cube of mass M=0.703 kg is placed on an incline and given a push. It slides down, and its speed down the incline is measured at two positions, [1] and [2] on the diagram below, with V1 = 0.923 m/s and V2 = 1.207 m/s. Note that the incline passes through at least two grid intersections and that one cube corner is at x grid lines.

Question

A cube of mass M=0.703 kg is placed on an incline and given a push. It slides down, and its speed down the incline is measured at two positions, [1] and [2] on the diagram below, with V1 = 0.923 m/s and V2 = 1.207 m/s. Note that the incline passes through at least two grid intersections and that one cube corner is at x grid lines.

A. Calculate mk, the coefficient of kinetic friction for the block on the incline.

The height of the Right triangle is .38m and the length is 1m

Ok here is where I have got so far.
Tan (theta) = .38m/1m
theta = 20.807 deg

Sum Fy=mg*sin(theta)-Fn=ma=0
.703kg(9.81)*sin(20.807)-Fn=o
Fn=2.45N

Sum Fx=mgcos(theta)-Ff=ma
.703(9.81)*cos(20.807)-mk(2.45)=.703*a

This is where I am stuck

Answer 1

You have not presented enough data in the statement. In following your calculations, I see you have dimensions. I am wondering if you have the distance, or time between the marks at V1, V2. If you have either, then you can determine acceleration down the incline, thence net force (gravity minus friction).