Application of Newton’s First Law of Motion
Let us look at a real-life example in which Newton’s first law of motion is demonstrated.
Assume that you are a passenger in a stationary car holding a cup of coffee filled to the rim. We will understand the first law with the help of these three parameters.
Real-life application of Newton’s first law of motion
Situation 1: As per Newton’s first law, an object continues to be in a state of rest,
unless acted upon by an unbalanced force.
That is, when the car is at rest, you, the coffee cup and the coffee, all are in a state of rest and will continue to remain at rest unless an unbalanced force acts on the car.
What will happen when the driver accelerates the car?
When the car accelerates, the engine’s driving force acts as an unbalanced force on the car. This unbalanced force sets the car in motion and in turn sets you, the coffee cup and coffee also in motion.
Situation 2: The first law also states that all objects continue to be in a state of motion unless acted upon by an unbalanced force.
Now assume that the car is moving with a uniform velocity. When the car is moving, you, the coffee cup and coffee all are in a state of motion and will continue to move with the same velocity unless an unbalanced force acts on the car.
What will happen when the driver applies the brakes on the moving car?
When the brakes are applied, the wheels get locked. The force of the road and the locked wheels provide an unbalanced force on the car which brings it to a halt. You, the coffee cup and coffee all being the part of the car also come to rest along with it.
But in both situations, there will be something else also that will happen.
When the car is accelerated, it moves forward but you will be pushed slightly in the backward direction. And when brakes are applied to the car, the car stops but you will be pushed slightly in the forward direction. Why do you think this happens? We will learn about this in the next segment.