Q.A child applies a force vec F parallel to the x-axis to a 10.0-rm kg sled moving on the frozen surface of a small pond. As the child controls the speed of the sled, the x-component of the force she applies varies with the x-coordinate of the sled. Suppose the sled is initially at rest at x=0. You can ignore friction between the sled and the surface of the pond. Use the work-energy theorem to find the speed of the sled at 3.0 m.
Q. A 50.0 ice skater spins about a vertical axis through her body with her arms horizontally outstretched, making 2.50 turns each second. The distance from one hand to the other is 1.5 . Biometric measurements indicate that each hand typically makes up about 1.25 of body weight.