What is the Newton’s law of motion?

DYNAMICS

Every object tends to resist any change in its speed or direction. This property is called inertia. An object’s motion is only changed when a force, such as a push or pull, is applied. A heavy, fast-moving object is described as having lots of momentum. The more momentum something has, the more difficult it is to stop. A moving object also possesses kinetic (movement) energy. The principles of dynamics, or how forces make things move, were explained by scientist Isaac Newton (1642-1727) in his three laws of motion.

NEWTON’S FIRST LAW The first law states that an object will stay still or continue to move at the same speed and in the same direction unless a force acts upon it. When cars approach each other in a crash-test laboratory, they move forward steadily. The dummies inside each car are carried along at the same speed as the car.

NEWTON’S SECOND LAW This states that when a force acts on an object, it makes the object change speed or direction. As the two cars collide, the front of each car exerts a force on the other car, slowing it down. The dummies inside are slowed down as they experience the force of the seatbelt.

NEWTON’S THIRD LAW The third law of motion says that when a force acts on an object, the object reacts by pulling or pushing back with equal force, but in the opposite direction. So, it is impossible for one car to push on the other without experiencing a push back with equal force.

  1. Inertia If the dummy has no seatbelt, inertia will keep it moving forward at the same speed until it is stopped by a part of the car that has been slowed down by the impact – such as the windscreen.
  2. Collision When two cars collide, kinetic energy is converted to other forms of energy, such as heat and sound, as the fronts of the cars crumple. This is called an inelastic collision.
  3. Momentum If a heavy lorry collides with a car, the lorry’s greater momentum pushes the car along for some distance, but cars of equal weight and speed are halted, as their equal but opposite moment cancel out.

Picture Credit : Google

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