Figure P6.26 Problems 26 and 27.

A 52 kg person on a merry-go-round is traveling in a circle with a radius of 2 m at a speed of 1 m/s. (a) What acceleration does the person experience?(b) What is the net horizontal force?(c) How does it compare with the person's weight?

A neutron star has a mass of 2.0 × 1030 kg (about the mass of our sun) and a radius of 5.0 x 103 m (about the height of a good-sized mountain). Suppose an object falls from rest near the surface of such a star. How fast would this object be moving after it had fallen a distance of 0.015 m? (Assume that the gravitational force is constant over the distance of the fall and that the star is not rotating.) V = J.

It is well known that runners run more slowly around a curved track than a straight one. One hypothesis to explain this is that the total force from the track on a runner's feet--the magnitude of the vector sum of the normal force (that has average value mgmg to counteract gravity) and the inward-directed friction force that causes the runner's centripetal acceleration--is greater when running around a curve than on a straight track. Runners compensate for this greater force by increasing the time their feet are in contact with the ground, which slows them down. For sprinters running at 8 m/s around a curved track of radius 16 m, how much greater (as a percentage) is the average total force on their feet compared to when they are running in a straight line?