Because the net force must be zero, we conclude that the magnitude of the force is 1500 newtons, and the direction is in the positive axis.
What is the magnitude and direction of the third force?
By Newton's laws, we know that if the net force applied to an object is different than zero, then the object is accelerated.
In this case, we know that the object moves with constant velocity, so there is no acceleration, meaning that the net force is equal to zero.
Then we must have:
F1 + F2 + F3 = 0N
Replacing F1 and F2 we get:
-3000 N + 1500N + F3 = 0
F3 = 3000N - 1500 N = 1500N
Then the magnitude of the force is 1500 newtons, and the direction is in the positive axis.
If you want to learn more about Newton's laws, you can read:
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