College Physics Problem 2.6

A helicopter blade spins at exactly 100 revolutions per minute. Its tip is 5.00 m from the center of rotation.
(a) Calculate the average speed of the blade tip in the helicopter’s frame of reference.
(b) What is its average velocity over one revolution?


a) The average speed of the blade tip is equal to the distance traveled divided by the time elapsed.

speed= frac{distance traveled}{time elapsed}

speed= frac{2 pi r}{t}

speed= frac{2 pi (5.00 m)}{60 s}times 100 rev=52.36 m/s

b) After one revolution, the tip of the blade is at the same position at it is originally. This means that the displacement is zero. Thus, the velocity is zero.

v=0 m/s