Q1. A 3.20 box that is several hundred meters above the surface of the earth is suspended from the end of a short vertical rope of negligible mass. A time-dependent upward force is applied to upper end of rope, and these results in the tension in the rope of. The box is at rest at. The only forces on the box are the tension in rope and gravity.
What is the velocity of the box at 1.20?
Q2. A boy is attempting to swim directly across a river; he is able to swim at a speed of 0.421 m/s relative to the water. The river is 2.48 m wide and the boy ends up at 4.77 m downstream from his starting point.
(a) How fast is the current flowing in the river?
(b) What is the speed of the boy relative to a friend standing on the riverbank?