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

I will be happy to critique your work.

The applied force (in the direction up the incline) must equal the sum of the friction force, which is
0.3*15N*cos 20
PLUS the component of the weight DOWN the incline, which is 15N sin 20

Answer 2

ok so its 15.53 n

Answer 3

5.13 + 4.23 does not equal 15.53 N