A box slides down a 30.0 degree ramp with an acceleration of 1.25m/s². Determine the coefficient of Kinetic friction between the box and the ramp.

Question

I'm not sure to work it out I draw a picture to see if it would help me but I'm still stuck..

Answer 1

normal force = m g cos 30

friction force up ramp = mu m g cos 30

gravity force component down ramp = m g sin 30

so
m g sin 30 - mu m g cos 30 = m (1.25)

mu = (g sin 30 - 1.25)/(g cos 30)