Net force of crewmen pulling boat?

Question

Two crewmen pull a boat through a lock. One crewman pulls with a force of size F1 = 135 N at an angle of = 31° relative to the forward direction of the boat. The second crewman, on the opposite side of the lock, pulls at an angle of 45°. How large a force F2 should the second crewman pull so that the net force of the two crewmen is in the forward direction?

Answer 1

Hi, Dorthy--

Draw a pic.  It really helps!

For the force to be all forward, the lateral forces must be equal..

so,

135 sin (31) = F sin (45)..you should get 98.3 N

The forward F will be what??

135 cos 31 + 98.3 * cos (45)

-Fred