A small block on a frictionless, horizontal surface has a mass of 2.80×10−2 kg . It is attached to a massless cord passing through a hole in the surface (Figure 1) . The block is originally revolving at a distance of 0.300 m from the hole with an angular speed of 2.67 rad/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.
pic link https://session.masteringphysics.com/problemAsset/2037525/2/YF-10-48.jpg
Part A
Is angular momentum of the block conserved?
a. yes
b. no
Part B
What is the new angular speed?
ω2 =
Part C
Find the change in kinetic energy of the block.
Express your answer with the appropriate units.
ΔK =
Part D
How much work was done in pulling the cord?
Express your answer with the appropriate units.