12. Rotational Kinematics

Which of the following are units for expressing rotational velocity, commonly denoted by $\omega$?

A fan blade is rotating and speeding up in the counterclockwise direction, which is defined as the positive direction. What are the signs of its angular velocity $\omega$ and angular acceleration $\alpha$?

Which of the following are valid units for expressing rotational velocity?

Calculate the rotational velocity (in rad/s) of a clock's minute hand. 

EXTRA:Calculate the rotational velocity (in rad/s) of a clock's hour hand.

A wheel of radius 5 m accelerates from 60 RPM to 180 RPM in 2 s. Calculate its angular acceleration.