Gravity is the attractive pull between two objects that have mass. The strength of the gravitational pull depends on mass and distance. As distance between the objects increases, the force of gravity decreases. If the distance is doubled, the force of gravity is one-fourth as strong as before. Which one of the graphs best represents the relationship between gravity and distance.

the duration of a photographic flash is related to an rc time constant, which is 0.100 μs for a certain camera.

the total distance that martina travels that day is

(distance from home to mom's office) plus (distance from mom's office to school)

plus (distance from school to library) plus (distance from library to friend's house)

plus (distance from friend's house to martina's house).

(we don't know what any of these distance actually is.)