A train was moving at 50m/s and slowed down to 20 m/s in 50 seconds, what was its acceleration?

Which term best describes the phrase “something that happens”?

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.

Curious carl calculated the density of a cube to be 4.50 g/cm3. what is the density of the cube in g/l?