The Universe Made Simple/Laws

Isaac Newton was one of the most famous and influential physicists of all time, discovering three fundamental laws of motion that continue to be applied to this day. His discoveries allowed for the progression of mathematics and physics at an exponential rate.

Newton's Laws

Newton’s First Law states that “an object at rest will stay at rest, and an object in motion will stay in motion, unless acted upon by an outside force.” If Earth’s gravitational pull and air resistance didn’t play a part, a ball thrown upwards would travel at the same speed indefinitely!

Newton’s Second Law states that Force is equal to Mass times Acceleration, with “acceleration” being a number representing how quickly an object is speeding up or slowing down. The harder you push on something, the more it will speed up! It’s important to understand that this equation refers to mass; not weight. Upon leaving Earth’s orbit, your weight will decrease, but your mass remains the same. Therefore, ignoring “outside forces,” (friction, gravity, etc.) it would take the same amount of effort to accelerate something on Earth as it would in space.

Newton’s Third Law states that “every action has an equal and opposite reaction.” If you exert a force on an object, it exerts the same force back on you! Obviously, you aren’t sent backwards when pushing a door open or kicking a soccer ball; friction, gravity, and your high mass cause the acceleration applied onto you to be almost entirely negated.