4. What force is needed to push a 15 N object up a 20° incline at constant speed when the coefficient of friction is 0.30?

Answer 1

Compute the friction force,
Ff = W*cos20*Uk
Add it to the component of the weight in the direction down the incline:
W sin20.
The applied force must equal the sum of those two forces if the object is yo move at constant speed up the incline.
Uk = 0.30
W = 15 N