Question

If the crate (drawn inside!) is moving at a constant speed in a straight line and the force applied is 310 N, what is the magnitude of the force of friction? 620 N, 155 N, 0 N, or 310 N ? ***not sure how to go about this:( thanks!!

Answer 1

If the object is moving at constant speed means acceleration is zero.

Then, you can use the second law of Newton, net force = mass * acceleration, to conclude that the net force on the object is nil.

That means that the force applided equals de force of friction in magnitud (of course in opposed direction).

force of friction - force applied = 0

Therefore: force of friction = force applided = 310 N.

Answer: 310 N