A small block on a frictionless, horizontal surface has a mass of 2.80 times 10-
ID: 1314112 • Letter: A
Question
A small block on a frictionless, horizontal surface has a mass of 2.80 times 10-2kg. It is attached to a massless cord passing through a hole in the surface the figure Figure 1 . The block is originally revolving at a distance of 0.300 m from the hole with an angular speed of 1.85rad/s . The cord is then pulled from below, shortening the radius of the circle in which the block revolves to 0.150 m. Model the block as a particle. Find the change in kinetic energy of the block. Part D How much work was done in pulling the cord?Explanation / Answer
change in K.E= 0.5m(w2r2-w2r1)
=0.5* 2.8*10-2*1.852(0.3-0.150)2
=1.078*10-3