A 130 kg box is placed on a frictionless incline with an angle of 24.0° above the horizontal. The box slides at constant velocity down the incline as you push it. Determine the magnitude of the force you apply if the force is parallel to the incline's surface.

A 125-g ball is attached to a light cable and spun counterclockwise in a vertical circle with a radius of 0.50 m. At the position where the ball is moving straight up, the ball is subject to a tangential force of magnitude 3.2 N and a centripetal force of magnitude 4.0 N. Calculate the direction of the net force on the ball with respect to the positive x-direction.

Bob observes his phone dangling from a cord while the train he is in accelerates out of the station, lasting about 18 s. If the cord forms an angle of 26° with respect to the vertical during this acceleration, estimate the speed of the train at the end of the 18 s.