What does the physics equation ef=0 mean?

Which of the following are considered noble gases? a. bromine b. neon c. argon d. chlorine

Which lists the organs in the correct order as food passes from the mouth to anus?

You are driving directly behind a pickup truck, going at the same speed as the truck. a crate falls from the bed of the truck to the road. (a) will your car hit the crate before the crate hits the road if you neither brake nor swerve? (b) during the fall, is the horizontal speed of the crate more than, less than, or the same as that of the truck?