What is Newton's first law? (article) | Khan Academy (2024)

Also called the law of inertia, this is the most important thing to realize about motion.

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  • varunkaarthik

    8 years agoPosted 8 years ago. Direct link to varunkaarthik's post “while watching the astron...”

    while watching the astronauts eating in the ISS, it got me thinking... does gravity affect blood circulation? ? i guess food has no problem in digesting because we have peristalitic movements in the esophagus to aid the movement of food. On the other hand the blood travelling through the veins and arteries are powered or made to move with the help of the heart, so does 0 - gravity affect the circulatory system? and therefore strain the heart??

    (37 votes)

  • Adarsh

    8 years agoPosted 8 years ago. Direct link to Adarsh's post “3rd Example : I get why t...”

    3rd Example : I get why the probe follows the straight movement but why it went diagonal is still not clear to me. Can someone elaborate that?

    Thanks for the help.

    (16 votes)

  • angelfromabove410

    9 years agoPosted 9 years ago. Direct link to angelfromabove410's post “how to the astronauts eat...”

    how to the astronauts eat in mid air there is no gravitational force pulling them down doesn't that hurt their bodies when they come down ?

    (9 votes)

    • Teacher Mackenzie (UK)

      9 years agoPosted 9 years ago. Direct link to Teacher Mackenzie (UK)'s post “great question. When they...”

      What is Newton's first law? (article) | Khan Academy (12)

      great question. When they swallow the food, the body pulls it down into the stomach. Its a special movement called 'peristalsis' (looks like a Caterpillar walking :-) and it pushes the food along the digestive system in a wave-like motion.
      I dont know if it hurts them when they land, but I guess they will feel various pains as they come back down to Earth, depending on how long they were up there. It would be an interesting quesiton to ask them.

      (22 votes)

  • Abderrahmane Taouil

    9 years agoPosted 9 years ago. Direct link to Abderrahmane Taouil's post “is dark matter considered...”

    is dark matter considered as an external force??

    (5 votes)

    • tharaisapprentice

      4 years agoPosted 4 years ago. Direct link to tharaisapprentice's post “I honestly don't know the...”

      I honestly don't know the answer to that. I would assume the answer is "yes", however, if you look at the universe as a singular body, dark matter and white holes could both be considered internal forces. This shows how suggestive internal and external forces can be.

      (7 votes)

  • sumitdongardiye035

    7 years agoPosted 7 years ago. Direct link to sumitdongardiye035's post “Sir,What will happen if w...”

    Sir,What will happen if we are in a lift and the cable of the lift breaks down.

    (3 votes)

    • Andrew M

      7 years agoPosted 7 years ago. Direct link to Andrew M's post “You will fall.”

      What is Newton's first law? (article) | Khan Academy (19)

      You will fall.

      (13 votes)

  • Ammar Hummieda

    9 years agoPosted 9 years ago. Direct link to Ammar Hummieda's post “In free fall, when an obj...”

    In free fall, when an object reaches terminal velocity, why does the force of drag (air resistance) become equal to the weight ? Why doesn't it become greater ? practically, this would be a silly question, but i want to know the theory behind it. Thanks a lot, I love your work and would love to one day contribute to this website as one if its own.

    (5 votes)

    • Andrew M

      9 years agoPosted 9 years ago. Direct link to Andrew M's post “Drag, like friction, is a...”

      Drag, like friction, is a reaction force. It can't be greater than the force that it is a reaction to. If it could, objects would reach terminal velocity and then start slowing down. But if they slow down, the drag force would decrease, so then they would speed up, and then slow down, and then speed up....

      (4 votes)

  • ❗〽〽ØR৳αL__G@MER

    3 years agoPosted 3 years ago. Direct link to ❗〽〽ØR৳αL__G@MER's post “Is there any time interva...”

    Is there any time interval between when the force is applied and when an opposite force is given?

    (3 votes)

    • Charles LaCour

      3 years agoPosted 3 years ago. Direct link to Charles LaCour's post “No, there is no lag betwe...”

      No, there is no lag between a force being applied and the reaction force.

      Let's consider what is happening when you push on an object. As your hand get close to the object the electrons in the outer shells of the atoms and molecules of your hand and the object start to interact. This interaction is the force on the object and your hand, you can't separate the force from the reaction force, they are all part of the same interaction.

      (4 votes)

  • tenzingyaltsen15

    6 years agoPosted 6 years ago. Direct link to tenzingyaltsen15's post “for the third question, w...”

    for the third question, while it is moving right and the rocket make short burst of force, it is moving equally in both the horizontal and vertical direction. So if things move equally in both the components, does it mean that we take the resultant force as the final direction?

    (4 votes)

  • Wejdan Almaoudi

    7 years agoPosted 7 years ago. Direct link to Wejdan Almaoudi's post “i didnt understand what i...”

    i didnt understand what is inertia ?

    (2 votes)

    • Mark Zwald

      7 years agoPosted 7 years ago. Direct link to Mark Zwald's post “Inertia is property of ma...”

      Inertia is property of mass. That property is maintaining momentum unless a force acts on it.

      (4 votes)

  • Anthony

    a year agoPosted a year ago. Direct link to Anthony's post “Example 2: how the answer...”

    Example 2: how the answer is b, not a. The elevator is moving upward at a constant velocity, and the magnitude of the upward force(Fc) is greater than the downward force(Fg).

    (3 votes)

    • Charles LaCour

      a year agoPosted a year ago. Direct link to Charles LaCour's post “If an object is moving at...”

      If an object is moving at a constant velocity it is not accelerating so there is no net force.

      (3 votes)

What is Newton's first law? (article) | Khan Academy (2024)

FAQs

What is Newton's first law? (article) | Khan Academy? ›

Newton's first law: An object at rest remains at rest, or if in motion, remains in motion at a constant velocity unless acted on by a net external force. Note the repeated use of the verb remains. We can think of this law as preserving the status quo of motion.

What is Newton's first law? ›

1. Newton's First Law of Motion (Inertia) An object at rest remains at rest, and an object in motion remains in motion at constant speed and in a straight line unless acted on by an unbalanced force. 2.

How do you introduce Newton's first law? ›

Newton's first law says an object remains at rest or in motion until a balanced force acts on it. That is common sense. An object doesn't move until you apply force, nor does it stop until you apply a counter force. For instance, a ball will keep rolling if there is no friction.

What is Newton's first law prac? ›

Newton's first law of motion says that an object in motion wants to stay in motion. Likewise, an object at rest will stay at rest until acted on by an outside force.

How do you prove Newton's first law? ›

If the body is initially at rest i.e., if u = 0, v = 0 and if u = 5 ms-1, v = 5ms-1. Thus, it follows that a body will continue to be in the state of rest or of uniform motion along a straight line if no external force acts on it and this is the first law. thus, first law can be deduced from second law of motion.

What is Newton's 2nd law? ›

Newton's second law states that the acceleration of an object is directly related to the net force and inversely related to its mass. Acceleration of an object depends on two things, force and mass. This shows that the bowling experiences a much greater force.

What is Newton's law for dummies? ›

Newton's 1st law tells us that an object won't change its motion unless acted upon by a force. Newton's 2nd law tells us that heavier objects need a larger force to move them. Newton's 3rd law tells us that for every action there is an equal and opposite reaction. WHAT ARE NEWTON'S LAWS OF MOTION?.

What is Newton's first law of motion 6th grade? ›

Station 1 – Newton's First Law: An object in motion stays in motion unless an unbalanced force acts upon it. Students should time each other pushing the tennis ball down the path marked with tape, using the ruler provided at the station.

How do you write Newton's first law as an equation? ›

We can give Newton's first law in vector form: v → = constant when F → net = 0 → N . v → = constant when F → net = 0 → N . This equation says that a net force of zero implies that the velocity v → v → of the object is constant.

What was the first law in the world? ›

The Code of Ur-Nammu is the oldest known law code surviving today. It is from Mesopotamia and is written on tablets, in the Sumerian language c. 2100–2050 BCE. It contains strong statements of royal power like "I eliminated enmity, violence, and cries for justice."

How did Newton create the first law? ›

Newton discovered the law of inertia by studying the results of Galileo Galilei. Galileo had noticed that smoother surfaces allow an object to move further down an incline that rougher ones. Newton then recognized that on a perfectly smooth surface an object could move forever if it did not encounter an opposing force.

Whose idea was Newton's first law? ›

Newton took Galileo's idea of inertia one step further. He stated in the Law of Inertia as translated from his Principia that: "Every object persists in its state of rest or uniform motion in a straight line unless it is compelled to change that state by forces impressed on it."

Why is it called Newton's law? ›

Newton's Laws of Motion are three physical laws which provide relationships between the forces acting on a body and the motion of the body, first formulated by Sir Isaac Newton. Newton 's laws were first published in his work Philosophiae Naturalis Principia Mathematica (1687).

What is Newton's 3 law? ›

What is Newton's Third Law? Newton's third law simply states that for every action there is an equal and opposite reaction. So, if object A acts a force upon object B, then object B will exert an opposite yet equal force upon object A.

What is an example of the first law of inertia? ›

If you are on a train and the train is moving at a constant speed, a toy tossed into the air will go straight up and then come down. This is because the toy has inertia like the train and you. If you jump from a car or bus that is moving, your body is still moving in the direction of the vehicle.

What is Newton's fourth law? ›

Newton's Law of gravitation is called Newton's fourth law. It states that every point mass attracts every other point mass by a force acting along the line intersecting both points. The force is proportional to the product of the two masses, and inversely proportional to the square of the distance between them.

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