A playground merry-go-round of radius 1.7 m has a moment of inertia 137 kg. m2 and is rotating at 10 rev/min about a frictionless vertical axle. Facing the axle, a 22 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.

The graph describes the motion of an object. the object moves with from a to b. it from b to c. it moves with from c to d.

Africtionless piston-cylinder contains 50 l of saturated liquid r-134a. the piston has a mass and an area resulting in an applied pressure of 500 kpa on the refrigerant. the refrigerant is now heated until its temperature rises to 70∘c. calculate the work (in kj) done during this process.

Electromagnetic induction. a coil of wire contains n turns and has an electrical resistance r. the radius of each turn is a. initially, inside the coil there exists a uniform magnetic field of magnitude b0 parallel to the axis of the coil. the magnetic field is then reduced slowly. the current induced in the coil is i. how long does it take for the magnitude of the uniform field to drop to zero?