A small block with a mass .120 kg is attached to a cordpassing through a hole in a frictionless, horizontal surface(fig.6.25). The block is originally revolving at a distance of .40m from the hole with a speed of .70 m/s. The cord is thenpulled from below, shortening the radius of the circle in which theblock revolves to .10 m. At this new distance, the speed ofthe block is observed to be 2.80 m/s.
a) What is the tension in the cord in the original situation when the block has speed v = .70m/s?
b) What is the tension in the cord in the final situation whenthe block has speed v = 2.80 m/s?
c) How much work was done by theperson who pulled on the cord?