Isaac Newton

The English scientist, theologian and mathemetician who formulated important laws of gravitation and physics. This category is designed to collect questions about the man, his work, and his philosophies.

14,690 Questions

Did Isaac newton discover that the solar system is held together by gravity?

Sir Isaac Newton's laws are named the 'Three Laws of Universal Dynamics'.

'Universal' because it means they apply on Earth and out in the Universe. 'Dynamics' , because it means movement.

So the laws refer to movement of all objects, be it on Earth or in Space.

The Three Laws are ;_

  1. An object(mass) will remain stationary or in uniform motion unless acted upon by a force.

  2. Force is directly proportional to acceleration, or Force is directly proportional to mass. ( F = ma)

  3. To every force there is an equal and opposite force.

In the story of the apple falling on his head, he perceived not only the apple falling to the ground (gravity), but infinitessimally the ground(Earth) moved towards the apple, because the apple has gravitational attraction.

NB It has been calculated that two VLCC's (supertanker ships) when berthed along side each other, they have a gravitational force of attraction of 0.5 kg.

What affects force?

Mass and acceleration. Force = mass x acceleration

What is an example of force mass acceleration?

It takes every human being on the planet to force the mass of your body to accelerate.

A total force of 2 Newtons on a mass of 3 Kg would cause the mass to accelerate at 6 metres/sec2. Note that the acceleration is caused by the sum of all forces, so if the mass is glued to a table top there is a resisting force which causes the net force to be zero. (or you might move the table too, but then you have a different total mass then, and friction on the floor resisting motion too).

If a moving body has no acceleration does it mean that no force is acting on it?

It means there is no net force acting on it.

A plane in the air has no acceleration, but it does have forces acting on it.

Lift pushes it up

Gravity pushes it down

Air resistance opposes its movement

Thrust provides movement

When all these forces are equal the plane will move at a constant velocity. If one of these forces becomes greater the NET force on the plane will no longer be 0 and there will be an acceleration or deceleration.

Hope that helps.

Another example would be space as there are no opposing forces, if in space once a speed was that speed would be constant until you 1.) decelerated with a force in the opposite direction 2.) accelerated the speed past your current velocity in your current direction 3.) Get caught by some planets gravity and crash to you death (but then this question is the least of your problems)

Which law proved that newton's gravity law is wrong?

Newton's Law of Gravity is not wrong, in macroscopic scale and at relatively low speed, it predicts the movement of objects accurately.

However, objects at microscopic scale near the speed of light will have to take into account time dilation, and General Relativity helps describes these.

How is inertia related to mass and acceleration?

Inertia is matter's unwillingness to slow down, speed up, or change direction in any way. It is also related to the matter's momentum. Momentum is caused by the body's velocity as well as the body's direction. If the velocity of the matter is increasing, or the body changes its direction, it can be said that the body of mass is experiencing inertia.

When the body is accelerating (changing in velocity), the momentum of the matter is also changing (F=ma), thus mass and acceleration is related by momentum through inertia.

Does everything need a force to move?

No force is required for an object to move with constant velocity, but you need a force to accelerate an object (make velocity increase or decrease).

The larger an object's mass the larger its.....?

The larger the objects mass the larger the inertia and also the gravitational force.

What sport displays newton's first law of motion?

the first law is:

An object at rest stays at rest and an object in motion stays in motion unless acted on by an outside force

so all of them.

-in golf, the golf ball will move when hit and stop only when gravity and friction make it happen.

in this case the ball is at rest on the tee and will not move until struck by the club (acting as ouside force 1), at which poin it then flies out until the friction of the air and gravity's pull force it back down to the earth, at which point friction with the ground is then added which all conspire to slow the ball to a stop.

-in foot ball, the players run with the ball until tackled by another player.

in this case the two players are the opposing forces

-in baseball the ball is thrown is moves toward the catcher until either the bat strickes it and it is sent elsewhere, or the catcher catches it and throws it back to the pitcher.

in this case the ball is the object and the bat and pitcher are the outside forces acting on the ball to give it motion.

What made Sir isaac Newton Famous in Math?

He discovered gravity when an apple fell on his big forehead. He discovered that the same force acts between the Sun and the planets to make them move in stable elliptical orbits. To do that he had to invent the laws of motion and also the differential calculus. Quite a feat that no-one else had managed, even after 1500 years of thinking (he died while thinking) about how the planets moved around.

Name one scientific contribution of Isaac Newton?

How about three. His three laws of motion. (Taken from Wikipedia)

  • First Law: Every body remains in a state of rest or uniform motion (constant velocity) unless it is acted upon by an external unbalanced force. This means that in the absence of a non-zero net force, the center of mass of a body either remains at rest, or moves at a constant speed in a straight line.
  • Second Law: A body of mass m subject to a force F undergoes an acceleration a that has the same direction as the force and a magnitude that is directly proportional to the force and inversely proportional to the mass, i.e., F = ma. Alternatively, the total force applied on a body is equal to the time derivative of linear momentum of the body.
  • Third Law: The mutual forces of action and reaction between two bodies are equal, opposite and collinear. This means that whenever a first body exerts a force F on a second body, the second body exerts a force −F on the first body. F and −F are equal in magnitude and opposite in direction. This law is sometimes referred to as the action-reaction law, with F called the "action" and −F the "reaction".

What is the relation between newton and dyne?

The newton comes from the MKS (kg-m-s) system

The dyne comes from the CGS (cm-g-s) system.

This means that:

1N=1 kg*m/s²

1dyn=1 g*cm/s²

And therefore that

1N=10^5 dyn

What is the example of law of inertia?

example for law of inertia - in moving car when the brakes are applied all of sudden the passengers lean forward because the brakes are applied on moving car and not on bodies of passengers. So bodies keep moving while the car retards.

example for law of acceleration - to move a standing object we need to apply force and to stop a moving object we need to apply brakes - this is law of acceleration.

law of interaction - when the horse pulls a cart, the cart pulls back the horse or when you hit a wall you get hurt as wall also hits you back.


It is quite simple, that is everything contains enertia i.e the reluctance to change what it is doing. The first answer is a good example. Both car and passengers travel at 40 kl per hr. The car breaks but the passengers still wish to move with a forward motion of 40 kl per hr.

The third answer is not quite correct. As the horses collar is attached to the cart therefore becomming part of it, the horse pushes the cart.

How does force vary acceleration at constant mass?

According to newtons laws of motion (F = ma) if you change the force acting upon an object it will be proportional to the mass X acceleration. For Example:

When F = 10NM M=5 Kg A= 2m^2

If you change the Force (F) to 20NM and the mass stays constant at 5 Kg you need to balance the equation so the acceleration will be the only thing to change. In this example the acceleration would need to be: 4m s^2

Why did Isaac Newton invent the reflecting telescope?

== == Newton did not invent the reflecting telescope. The first reflecting telescope is credited to Niccolò Zucchi in 1616. In 1668, Isaac Newton made significant improvements to the design resulting in a much improved reflecting telescope that still bears his name, the "Newtonian reflector." He did it because the refracting (lens) telescopes of the day suffered severe color aberration. (Different focal lengths of different colours of light resulting in a blurred image because all the colours can't be brought into focus at the same time.) Reflecting telescopes do not suffer from color aberation and Newton's improvements made them effective observing instruments. Although the colour aberration of refractors was partially solved by the invention of the achromatic lens in 1733 Newton's design remains in use to this day.