If the distance between two asteroids is halved, the gravitational force they exert on each other will

a) also be doubled
b) be half as great
c) be one fourth as great
d) will be 1/16 as great
e) be four times greater

Which of the following elements is in the same period as phosphorus? a. carbon c. nitrogen b. magnesium d. oxygen select the best answer from the choices provided a b c d

Mutt and jeff are running along a path each pushing a cart loaded with rocks. if mutt's wagon has a mass two times greater than jeff's and they want to stay together, arriving at their destination at the same time, what must happen? a) jeff should slow down so mutt can catch up. b) mutt must use half as much force to push his cart. c) mutt must use twice as much force to push his cart. d) mutt and jeff will use the same force, but mutt will take bigger steps.

What are similarities and differences of reflection, refraction, diffraction and absorption?