Newton's Law of Motion - First, Second & Third - Physics

The Organic Chemistry Tutor26 minutes read

Newton's laws of motion explain the behavior of objects at rest and in motion, including the role of forces like weight, friction, and momentum. These principles underline how forces impact acceleration and velocity, shaping an object's movement in various scenarios.

Insights

  • Newton's first law of motion states that objects remain at rest or in motion unless acted upon by an external force, emphasizing the concept of inertia.
  • Newton's second law of motion explains how the net force on an object is directly proportional to its mass and acceleration, highlighting the fundamental relationship between force, mass, and motion.

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Recent questions

  • What is Newton's first law of motion?

    An object at rest stays at rest unless acted upon.

  • How is weight force calculated?

    Weight force = mass x 9.8 m/s^2

  • What is Newton's second law of motion?

    An object in motion stays in motion unless acted upon.

  • What is momentum in physics?

    Mass multiplied by velocity determines an object's motion.

  • What is Newton's third law of motion?

    For every action, there is an equal reaction.

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Summary

00:00

Newton's Laws: Motion, Force, and Interaction

  • Newton's first law of motion states that an object at rest will remain at rest unless acted on by an imbalanced force.
  • The weight force of an object can be calculated by multiplying its mass by the gravitational acceleration (weight force = mass x 9.8 m/s^2).
  • The normal force exerted by the ground on an object must balance the weight force to keep the object at rest.
  • An object in motion will continue in motion unless acted on by a net force, as per Newton's second law of motion.
  • Friction between surfaces can affect the motion of objects, with less friction allowing objects to travel further.
  • In outer space, where there is virtually no friction, objects can continue moving without external forces acting on them.
  • The net force on an object is equal to the product of its mass and acceleration, as per Newton's second law.
  • Momentum, calculated as mass multiplied by velocity, determines an object's motion and is crucial in understanding force interactions.
  • Newton's third law of motion states that for every action, there is an equal and opposite reaction force.
  • Examples illustrating Newton's third law include scenarios with objects of different masses experiencing different accelerations due to the same force.

20:10

Forces, Acceleration, and Motion in Physics

  • To travel in space, throw a ball in the opposite direction of where you want to go, such as towards the moon to be pushed in that direction.
  • When an object moves with constant velocity, the net force acting on it is zero, leading to zero acceleration.
  • If the frictional force on a car is 1500 newtons, the force applied by the engine must also be 1500 newtons to maintain zero acceleration.
  • Applying a force of 200 newtons on a 10-kilogram box on a frictionless surface results in an acceleration of 20 meters per second squared.
  • After 8 seconds, the box's speed will reach 160 meters per second if starting from rest and accelerating at 20 meters per second squared.
  • It will take 25 seconds for the box to reach a speed of 500 meters per second if accelerating at 20 meters per second squared.
  • A net horizontal force of 100 newtons acts on a 20-kilogram box, resulting in an acceleration of 5 meters per second squared.
  • The box will travel 360 meters in 12 seconds if accelerating at 5 meters per second squared from rest.
  • An object with a mass of 8 kilograms accelerates from 20 to 50 meters per second in 6 seconds, resulting in an acceleration of 5 meters per second squared.
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