1. How do astronomers know what the outer layers of the Sun are made of? a. we send graduate students there to get samples b. several spacecraft with good shielding have approached the Sun and obtained samples c. the surface layers of Mercury have been laid down by the Sun and are thus made of the same material as the Sun d. the Sun's wind gives us an accurate measure of all the different elements in the Sun e. we take an absorption line spectrum of the Sun, and the absorption lines tell us what elements are present in the outer layers

An insurance company wants to know if the average speed at which men drive cars is higher than that of women drivers. the company took a random sample of 27 cars driven by men on a highway and found the mean speed to be 72 miles per hour with a standard deviation of 2.2 miles per hour. another sample of 18 cars driven by women on the same highway gave a mean speed of 68 miles per hour with a standard deviation of 2.5 miles per hour. assume that the speeds at which all men and all women drive cars on this highway are both approximately normally distributed with unknown and unequal population standard deviations.

What is the momentum of a 2 kg object moving at 15 meters per second

Erosion of the beach is normally a slow process. however, in certain situations, large chunks of shore may wash out to sea. what could cause this to happen?