A55.0-kg woman stands at the rim of a horizontal turntable having a moment of inertia of 540 kg · m2 and a radius of 2.00 m. the turntable is initially at rest and is free to rotate about a frictionless vertical axle through its center. the woman then starts walking around the rim clockwise (as viewed from above the system) at a constant speed of 1.50 m/s relative to the earth.
(a) in what direction does the turntable rotate? counterclockwise or clockwise
with what angular speed does the turntable rotate? ? rad/s
(b) how much work does the woman do to set herself and the turntable into motion? ? j

a) ω = 0.305 rad/s counterclockwise

b) W = 61.875J

Explanation:

The angular speed of the woman is:

By conservation of the angular momentum:

 where ωo = 0

Solving for :

Work done by the woman is given by the variation on her kinetic energy:

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation: