Which scientists contributed to discovering the universal law of gravitation? check all that apply. tycho brahe albert einstein johannes kepler nicolaus copernicus sir isaac newton robert hooke

Kepler's laws explain how the planets moved around the sun but not why. Newton filled in that gap by supposing there was a force acting between the bodies that were moving around each other.

The story goes that Newton saw an apple fall to the ground and it made him wonder why the fruit always fell straight to the ground; why did it not veer off to the left or right? According to his own laws of motion, anything that begins moving from a standing start is undergoing acceleration and, where there is acceleration, there must be a force.

 The apple started in the tree and landed on the Earth, which means there must be a force of attraction between the apple and the Earth.

beta is electron from nucleus

something from nucleus has changed, but charge must be same for cons of charge