Step-by-step explanation:
Fn= normal force ( this determines the Ff friction)
Fn = mg cosΘ = 3.7 * 9.81 cos (21 ) = 33.88 N
Ff = 33.88 N * .17 = 5.76 N
Fdp = force downplane = mg sinΦ = 3.7 * 9.81 sin 21 = 13.01 N
Total forces acting down the plane = 13.01 + 5.76 = 18.77 N
T = The force acting up the plane to move and accelerate the block
Then :
F= ma
(T - 18.77 N) = 3.7 kg ( .3 m/s^2 )
T = 19.88 N