Solve Physics Problem: Coefficient of Friction on Steep Incline with Supertruck

[Charlie Brown]

A supertruck is fighting its way up an steep 65 degree incline with an acceleration of 3.3 m/s^2. If the truck has a mass=1.00 tonne and an engine applied force of 1.55 X 10^4 Newtons, find the co-efficient of friction.

1 tonne = 1000 kg

**I got 0.80 as my answer...can anyone confirm this?

 

[whozum]

Find the magnitude of gravity down the slope
Find the ideal acceleration of the truck by dividing force and mass.
Find a net force from the above two forces.
Find a net acceleration from this net force. (Divide by mass)
Compare this net acceleration to the acceleration provided.
Find the friction force by subtracting the two forces.
Divide by the normal force to get coefficient of friction.
Normal force is mgcos(\vartheta)

 

[Charlie Brown]

Find the magnitude of gravity down the slope
Find the ideal acceleration of the truck by dividing force and mass.
Find a net force from the above two forces.
Find a net acceleration from this net force. (Divide by mass)
Compare this net acceleration to the acceleration provided.
Find the friction force by subtracting the two forces.
Divide by the normal force to get coefficient of friction.
Normal force is mgcos(\vartheta)

Thank you...is 0.801 the answer?

 

[endeavour]

Resultant force = ma

let friction = F.

so, resolving forces parallel to the slope, using g=9.81N/kg:
F = ma
1.55*10^4 - F - 1000gcos65 = 1000*3.3
F= 8054 N

F=uR, where u = coefficient of friction
u = F/R
u = 8054/(1000*9.81)
u = 0.82