1. Why Applications of Newton’s Laws Matter
Newton’s laws are not just classroom concepts — they explain almost every action around us. Walking, running, jumping, driving, playing sports, and even launching rockets are all governed by these laws.
Understanding these applications helps us see how forces affect our daily activities in simple and predictable ways.
1.1. How Newton’s Laws Work Together
All three laws often act at the same time:
- The first law explains natural tendencies (rest/motion).
- The second law explains how force changes motion.
- The third law explains interactions between objects.
2. Walking and Running
Walking and running use Newton’s third law. When you push the ground backward, the ground pushes you forward with an equal and opposite force.
2.1. Why You Move Forward
Your foot applies an action force backward on the ground. The ground applies a reaction force forward on your body. This reaction force makes you move forward.
2.2. Role of Friction
Friction acts between your foot and the ground, helping you push backward effectively. Without friction (like on ice), walking becomes nearly impossible.
3. Swimming
Swimming is another example of Newton’s third law. When a swimmer pushes water backward with hands and legs, water pushes the swimmer forward.
3.1. Action–Reaction in Water
The harder a swimmer pushes water backward, the faster the swimmer moves forward due to an equal and opposite reaction force.
4. Rocket Propulsion
Rockets move upward because of Newton’s third law. Hot gases are expelled downward at high speed, and the rocket moves upward with an equal force.
4.1. Why Rockets Work Even in Space
Rockets do not need air to push against. They move because gases push downward, and the rocket receives the opposite push upward.
5. Using Seatbelts and Airbags
Seatbelts and airbags use Newton’s first and second laws to protect passengers during accidents.
5.1. Why Seatbelts Are Necessary
When a car stops suddenly, passengers tend to continue moving forward due to inertia (first law). Seatbelts apply an unbalanced force to stop them safely.
5.2. How Airbags Reduce Injury
Airbags increase stopping time during a collision. According to the second law, increasing stopping time reduces the force on the passenger, lowering the risk of injury.
6. Sports Applications
Newton’s laws play a huge role in almost every sport — cricket, football, basketball, tennis, athletics, and more.
6.1. Hitting a Ball
When a bat hits a ball, the ball experiences a large force for a short time (impulse). The ball’s momentum changes quickly and it speeds off in the opposite direction.
6.2. Jumping and Landing
Jumping pushes the ground downward (action), and the ground pushes the athlete upward (reaction). Landing on soft surfaces increases stopping time and reduces force.
7. Vehicles in Motion
Newton’s laws help explain how vehicles speed up, slow down, turn, and remain stable.
7.1. Acceleration and Braking
Based on the second law, applying more force on the accelerator increases acceleration. Brakes apply an unbalanced force opposite to motion, reducing speed.
7.2. Turning a Vehicle
Changing the direction of motion requires a force. Friction between tires and road provides the sideways force needed for turning.
8. Lifting and Carrying Objects
Lifting objects requires applying a force greater than their weight. This demonstrates Newton’s second law, where acceleration depends on both force and mass.
8.1. Heavy Objects Have More Inertia
Because heavier objects have more inertia, they require greater force to lift, push, or stop.
9. Why Doors Have Handles Far from Hinges
Though related to rotation, this uses Newton’s laws indirectly: applying the same force at a longer distance from the hinge produces greater turning effect, making the door easier to open.
9.1. Force and Turning Effect
Applying force closer to the hinge requires much more effort. This is why handles are placed at the edge of the door.