7) A pH of 4 is how many times more acidic than a pH of 7?

15. one purpose of the tread pattern on a tire is to a reduce tire wear. b. reduce traction c. allow water to flow away from the tire. d. look impressive.

Identify the theory that can be used to explain each phenomenon. answers diffraction: wave theory interference: wave theory reflection: both particle and wave theories refraction: both particle and wave theories

Awind turbine is rotating counterclockwise at 0.5 rev/s and slows to a stop in 10 s. its blades are 20 m in length. (a) what is the angular acceleration of the turbine? (b) what is the centripetal acceleration of the tip of the blades at t=0s? (c) what is the magnitude and direction of the total linear acceleration of the tip of the blades at t=0s?