The Laws of Motion
The first law of motion – this law states that an object at rest tends to stay at rest and an object in motion tends to stay in motion until an external force acts upon the object to make it move or bring it to rest, as the case many be. The reason for this is known as ‘inertia’. Inertia can be described as the resistance to force. Force must overcome the object’s inertia in order to make it move, bring it to rest, speed it up, or slow it down; the heavier the object, the greater the inertia.
The second law of motion – this law states that the acceleration of an object depends on the force applied to it. This means that the force producing that acceleration will be equal to the mass of the object multiplied by the mass of the object. So, acceleration will increase if the force applied increases and vice versa. This also means that the acceleration of the object will decrease if the mass of the object increases, and again vice versa.
The third law of Motion – This states that for every action there will always be an equal action in the opposite direction. The example of a rocket shooting up into space is the simplest to understand. The hot gasses rush out of one end of the rocket and since the rocket is free to move, it moves in the opposite direction of the gases. The movement of the rocket is always equal to the force of the gases rushing out. The faster the gases rush out the end, the faster the rocket will move in the opposite direction.
In recent years, modern scientists, such as Albert Einstein, came up with laws of relativity that redefined earlier laws of motion. Though, those laws are still referred to, in order to understand the basic concept of motion, a lot has changed.
- For instance, according to Italian astronomer and physicist Galileo if a person traveling in an airplane at 500 miles an hour were to throw an object forward in the direction of the motion of the airplane at a velocity of 10 miles an hour, the object would appear to travel at a velocity of 510 miles an hour to a person who is stationary on the ground. However, to a person in the same airplane, the ball would be traveling at just 10 miles an hour.