The concept of force derives from Newton’s laws, which describe force as the quantity that causes changes in motion of physical objects. In other words, forces change momentum of physical bodies, makes them accelerate or rotate. According to Newton’s first


When a ball rolls down a cliff, it gains momentum. When a car speeds up on a racing track, it gains momentum. In both cases, the velocity of the object is changing. Momentum is often described as mass times velocity

Mass and Weight

Weight is something that we are all familiar with, it is how “heavy” something is. It is related to, but not equal to your mass. e.g. the astronauts on the International Space Station have the same mass as they did

Newton’s second law of motion

Equation #5: law of motion Newton’s second law, as it was written, states that “the alteration of motion is ever proportional to the motive force impress’d; and is made in the direction of the right line in which that force