Aceiling fan is turned on and reaches an angular speed of 120 rev/min in 20 s. it is then turned off and coasts to a stop in an additional 40 s. the ratio of the average angular acceleration for the first 20 s to that for the last 40 s is which of the following?

a.2
b.-0.5
c.0.5
d.-2

(01.02 mc) nicole pushes her bike up a hill. overhead, the sun exerts a gravitational force on earth. which statement is true about the bike and earth? they both experience contact forces. they both experience non-contact forces. the bike experiences a non-contact force and earth experiences a contact force. the bike experiences a contact force and earth experiences a non-contact force. they both experience non-contact forces.