A 20 kg wagon is pulled along the level ground by a rope inclined at 30 deg above horizontal. A frictional force of 30 N opposes the motion, how large is the pulling force if the wagon is moving at constant velocity?

Answer 1

m*g = 20kg * 9.8N/kg = 196 N = Wt. of the wagon.

Fap*Cos30 - Fk = m*a
Fap*cos30-30 = m*0 = 0
Fap*cos30 = 30
Fap = 30/cos30o = 34.6 N. = Force applied.