What volume will be occupied by 20g of Copper if the density of Copper is 9.1g/ml?

What is the temperature in degrees celsius of a substance with a tempature of 49k

Which of the following are appropriate acceleration units?

Two point charges are separated by a certain distance. how does the strength of the electric field produced by the first charge, at the position of the second charge, change if the second charge is doubled? a. the field does not change b. the field strength decreases by half. c. the field strength doubles d. the field strength quadruples