9. Tectonic plates are large segments of the Earth's crust that move slowly. Suppose that one such plate has an average speed of 4.0 cm/year. 

(a) What distance does it move in 1 s at this speed?

(b) What is its speed in kilometers per million years?

 

10.  A good-quality measuring tape can be off by 0.50 cm over a distance of 20 m. What is its percent uncertainty?

11. 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?