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Newton

KinematicsAtomic Structures

Sir Isaac Newton1642-1727 (age 84)

“If I have seen further it is by standing on the shoulders of Giants”

Know for:• Newtonian mechanics• Universal gravitation• Calculus • Optics• And much more

1st law of motion 2nd law of motion 3rd law of motion

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Newton’s First Law -

“If no force acts on a body, the body’s velocity cannot change; that is, the body cannot

accelerate”

Simply put: if an object were to be travelling at a constant velocity in an ideal frictionless plane, that objects velocity would remain constant unless an external net force were to act upon the object. Alternatively, a stationary object would remain motionless unless acted on by an external net force

If Fnet=0, no change in motionIf Fnet≠0, a change in motion will occur

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Newton’s Second Law –

“The net force on a body is equal to the product of the body’s mass and its acceleration”

Simply put: An object undergoing a form of acceleration, such as an object falling under gravity or a car accelerating on a road, is subject to exhibiting a force. That force that the object has is the product of its mass and its acceleration. If an object has multiple forces acting on it, the net force provides the acceleration.

Fnet=ma

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Newton’s Third Law –

“When two bodies interact, the forces on the bodies from each other are always equal in magnitude and opposite in direction”

Or“Every action has an equal and opposite reaction”

Simply put: If you wanted to jump up in the air, instead of driving your body upwards, you actually push the Earth downwards. In turn the Earth reacts to this force equally on you but in the opposite direction, forces you to accelerate into the air. The earth moves also, however due to the comparative size of objects, the Earth’s movements is negligible .

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Atomic StructureAtoms are comprised of three basic building blocks

Electrons Protons Neutrons

Which do you want to learn about first?

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Electrons

Electrons are the negatively charged particles of the atom. They orbit the atom in ‘shells’.They are extremely small, even when compared to the size of a proton. The radius of each electron (according to the quantum mechanics model) is approx. 10-22m. This means it is 0.000 000 000 000 000 000 000 01m in diameter. To put this in perspective, if you imagined a 5c piece to be the size of an electron, then an actual 5c piece would extend more than twice the distance from the Sun to Pluto.Electrons are an elementary particle, meaning that they are not known to have any substructure

Back to homePeriodic Table Atomic Structure

Protons

Protons are the positively charged particles of an atom. They remain in a fixed location at the centre or ‘nucleus’ of an atom with the neutrons.Protons and neutrons are roughly the same size and mass. Each proton is 1.6-1.7fm (0.000 000 000 000 001m) in diameter and weighs about 10-27kg.Protons are not elementary particles, meaning that they have a substructure. Each proton is made of 2 up quarks and 1 down quark

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Neutrons

Neutrons are the neutrally charge particles of the atom. They are essentially the glue that holds the nucleus together. Without it, the protons would repel from each other causing an atom to disintegrate. Protons and neutrons are roughly the same size and mass. Each Neutron is 1.6-1.7fm (0.000 000 000 000 001m) in diameter and weighs about 10-27kg.Neutrons are not elementary particles, meaning that they have a substructure. Each Neutron is made of 1 up quark and 2 down quarks

Back to homePeriodic Table Atomic Structure

The Periodic table of elementsEvery atoms contains three particles; electrons, protons and neutrons. However, every atom also contains a differing number of these three particles depending on what element they are from. For instance a hydrogen only contains one electron and one proton, whereas a Caesium atom contains 55 Protons and Electrons, and 77 neutrons.The atomic number of an element is given by how manyelectrons or protons it has. In this picture, you can seeIron has an atomic number of 26, meaning it also has26 protons. The number below its symbol (Fe) is thenumber of protons and neutrons at its nucleus. Therefore Iron has approx. 30 neutrons.

Back to homeIsotopesView the Periodic TableAtomic Structure

Back to homePeriodic Table Atomic Structure Isotopes

IsotopesIron has 30 neutrons but 55.85 particles at its nucleus, why? This is because that number is simply an average for that element. Every element has what is called an ‘Isotope’. Isotopes are the same element but with a differing amount of neutrons at its Nucleus. There is still the same number of protons and electrons. Every element has an isotope. The most constant element (the one that forms the least amount of isotopes naturally) is Hydrogen. Hydrogen is almost exclusively neutron-less. The larger an atom, the more likely it is to form isotopes.

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KinematicsKinematics is the study of motion. It studies subject such as; displacement, velocity and acceleration.In kinematics, the important thing to note is not what causes the motion, i.e. a force, but simply the motion itself.

Back to homeDisplacement Velocity Acceleration

DisplacementDisplacement is the difference between the starting position and the end position. This is not the same as distance. A runner, on an oval completes one lap of a 600m oval, he has travelled a distance of 600m. However, he has not displaced himself at all (when referenced from his end state).Displacement is measured in the international standard unit metres (m).

Velocity Acceleration Back to homeKinematics

VelocityVelocity is the change in displacement over time. It is usually use for instantaneous velocity, i.e. the velocity at any given moment with respect to time, however it can also be used as an average. If that same runner travelled a displacement of 100m in 10seconds, then that runner would be travelling with an average velocity of 10m/s.Velocity is a function of time and displacement, making it a vector. Vectors have both a magnitude and a direction.The use of velocity can be tricky. For instance, if you were to look at the end of the runner lap, it would seem he had a velocity of 0m/s, but if you looked at his instantaneous velocity it would be very different

Displacement Acceleration Back to homeKinematics

AccelerationAcceleration is the change in velocity for any given time. It is measured in m/s2. An object undergoing acceleration experiences a changed in velocity; if it is a positive acceleration the velocity will increase, if it is a negative acceleration its velocity will decrease. In the case of gravity, the acceleration is either negative or positive depending on the motion of the object. Earths gravity is roughly 9.8m/s2. This means that after 1 second of free fall an object will be travelling at 9.8m/s, after 2 seconds it will be travelling at almost 40m/s.

Kinematics Displacement Back to homeVelocity