Problem 7.12 The earth's radius is 6.37Ã—106m; it rotates once every 24 hours. Part A What is the...
Problem 7.12
The earth's radius is 6.37Ã—106m; it rotates once every 24 hours.
Part A
What is the earth's angular speed?
Express your answer using two significant figures.
Part B
Viewed from a point above the north pole, is the angular velocity positive or negative?
Viewed from a point above the north pole, is the angular velocity positive or negative?
positive 
negative 
zero 
The angular velocity cannot be determined on the north pole. 
Part C
What is the speed of a point on the equator?
Express your answer to two significant figures and include the appropriate units.
Part D
What is the speed of a point on the earth's surface located at 1/3 of the length of the arc between the equator and the pole, measured from equator ? (Hint: what is the radius of the circle in which the point moves?)
Express your answer to two significant figures and include the appropriate units.
Problem 7.46
A 240 g , 23cmdiameter plastic disk is spun on an axle through its center by an electric motor.

Part A
What torque must the motor supply to take the disk from 0 to 2000 rpm in 4.2 s ?
Express your answer using two significant figures.


Sasha Henry
20Feb2020