A playground merry-go-round of radius 2.1 m has a moment of inertia 287 kg. m2 and is rotating at 10 rev/min about a frictionless vertical axle. Facing the axle, a 33 kg child hops onto the merry-go-round, and manages to sit down on the edge. What is the new angular speed of the merry-go-round? Answer in units of rev/min.

Athin, square metal plate measures 14 cm on each side and has emissivity of 0.60. the plate is heated to a temperature of 745°c. what is the rate at which the plate radiates energy ? the stefan-boltzmann constant is 5.67 × 10-8 w/(m2 ? k4). remember that the plate will radiate energy from both its top and bottom surfaces.

Determine the amount of work done when a crane lifts a 100-n block form 2m above the ground to 6m above the ground

Photoelectrons with a maximum speed of 6.50 x 107 m/s are ejected from a surface in the presence of light with a frequency of 6.75 x 1014hz. if the mass of an electron is 9.10 x 10-31 kg, calculate in joules the maximum kinetic energy of a single electron. 3.84 x 10-15 j 1.92 x 10-15 j 5.92 x 10-23 j 3.07 x 10-16 j