Suppose you are wearing sunscreen with SPF 20. How much of the sun’s UV radiation will be absorbed by the sunscreen? How much will penetrate your skin?

What happens when a rubber rod is rubbed with a piece of fur?

Wavelength of 125 meters is moving at a speed of 10 m/s. what is it's frequency?

The safe load, l, of a wooden beam of width w, height h, and length l, supported at both ends, varies directly as the product of the width and the square of the height, and inversely as the length. a wooden beam 4 inches wide, 9 inches high, and 240 inches long can hold a load of 6810 pounds. what load would a beam 3 inches wide, 8 inches high, and 144 inches long, of the same material, support? (round off your answer to the nearest integer.)