Two horses on opposite sides of a narrow stream are pulling a barge up the stream. each hors pulls with a force of 720n. the ropes from the horses meet at a common point on the front of he barge. what is the resultant force exerted by the two horses if the angle between the rope is 60 degrees?

For the answer to the question above, each horse's force forms a right angle triangle with the barge and subtends an angle of 60/2 = 30°. The resultant in the direction of the barge's motion is:
Fx = Fcos(∅)
We can multiply this by 2 to find the resultant of both horses.
Fx = 2Fcos(∅)
Fx = 2 x 720cos(30)
Fx = 1247 N