Gravity
Every body in the universe attracts every other body with a force that, for 2 bodies, is directly proportional to the product of their masses and inversely proportional tot he square of the distance between their centers.
Tides that occur when the moon is midway b/n new and full, in either direction. Tides due to the sun and moon partly cancel, making the high tides lower than average and the low tides higher than average.
Neap Tides
A law that relates the intensity of an effect to the inverse square of the distance from the cause.
Inverse-Square Law
A concentration of mass that results from gravitational collapse, near which gravity is so intense that not even light can escape.
Black Hole
The force that an object exerts on a supporting surface, which is often, but not always, due to the force of gravity.
Weight
High or low tides that occur when the sun, Earth, and moon are all lined up so that the tides due to the sun and moon coincide, making the high tides higher than average and the low tides lower than average.
Spring Tides
Being without a support force, as in free fall.
Weightlessness
The influence that a massive body extends into the space around itself, producing a force on another massive body; measured in N/kg.
Gravitational Field