All of the following are si base units except: a. meter
b. gram
c. second
d. kelvin
e. mole

Which statement is true? a. kepler's laws apply only to the motion of earth. b. kepler's laws can be used to predict eclipses. c. kepler's laws are true for a central force that is directly proportional to distance. d. kepler's laws can be deduced from newton's laws of motion and gravity.

Who was the first scientist to measure speed as distance over time?

You've already seen the value of 9.8 in this lesson. what's this value called? what quantity does it represent?