Topics in PhysicsDerived Units: Similarities and Differences with Fundamental Units Gravity: Interesting facts on Gravity Relative Density of Substances and Specific Gravity Types of Heat Transfer: Conduction Types of Heat Transfer: Convection Types of Heat Transfer: Radiation Physics Scheme of Work, SS1, First Term Physics Scheme of Work, SS1, Second Term Physics Scheme of Work, SS1, Third Term Velocity and Acceleration Newton's Laws of Motion Importance of Gravity What is Density? Density of various Substances Concepts of Force and Motion Motion and Speed Concept of Heat Transfer Concepts of Heat and Temperature Gravity: What is Gravity? Zeroth Law of Thermodynamics - Thermal Equilibrium Fundamental Quantities and Units in Physics
Academic Questions in Physics
The Law of Inertia is also referred to as _____.
The process whereby the velocity of an object increases and decreases over a period of time is best associated with the term _____.
The rate of motion is best referred to as _____.
Consider this expression below:
A body X exerts a force FX on another body Y. In return, body Y exert a force FY back on body X. The forces FX and FY are equal in magnitude but opposite in direction.
Putting the above expression into equation:
FX = -FY
Where FX is the action force
FY is the reaction Force
The above expression relates to _____.
The tendency of a body to remain in a state of rest or in uniform motion is referred to as _____.
A change in the position of an object with reference to time is best described as _____.
The saying "what goes up on earth must come down" can be best attributed to _____.
We have _____ laws of Thermodynamics.
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Gravity is a force of attraction. The exact reason why it’s pulling all things is yet to be ascertained by scientists.
Gravity is defined a natural force that pulls (or attracts) a body towards the center of the earth. It's also defined as a force that pulls a physical body with a lesser mass to another body with a greater mass. You may think of gravity as magnet that pulls together anything that has mass.
Mass is defined as the quantity or amount of matter a body has.
The earth is governed by the force of gravity and that’s why everything present on it (humans, plants, animals and even air) is always drawn towards it. You will actually need some form of force greater than gravity in order to pull yourself away from the earth.
As an instance, the earth as we know is spherical in shape and held in space. Also, all humans live on a constantly rotating earth and not inside the earth. Since we live on a spherical earth held in space, how come humans are yet to fall off the constantly rotating earth?
Well, the answer is gravity. Even if we attempt to jump off the earth into space, the force of gravity present on earth will still pull us down. In fact, in order to leave the earth; there has to be a force stronger that gravity; which must be applied to whatever is attempting to leave the earth. For this reason:
Whenever one jumps, a certain amount of force is needed to be applied by that person. However, gravity still return the person back to earth because the applied force had been exhausted.
Planes and jets leave the earth and remain in the atmosphere simply because force is constantly applied to it; and this force is always stronger than gravity throughout its flight.
Note: Gravity holds the air we breathe towards earth. As you move away from the earth, the air becomes thinner until it vanishes. This is why astronauts wear oxygen mask when they are in space.
It is important to understand that gravity is not even (the same) all round the surface of the earth. It is slighter stronger on earth surfaces with a greater mass underground than those with lesser masses.
The gravity on earth has also got some impact on its satellites.
Think of a satellite as either a machine or moon or planet that revolves around a larger body.
The earth has got one natural satellite (that's the moon) and many artificial satellites.
Note: The earth is also a satellite because it revolves round the sun.
The earth's natural satellite (moon) constantly revolves around the earth because the earth draws it closer to itself via the force of gravity. Even the moon has its own force of gravity. In short, everything in the universe have got gravity acting on them and that’s why they are all held in space. This will include all the planets, the moon, sun, stars and other components of the solar system.
Note: The larger the size of an object, the greater it’s force of gravity. Gravity is therefore affected by the size and closeness of objects.
Since the earth is larger than the moon, it will have a greater gravitational force than the moon. We will be more attracted on the earth than we would on the moon if we were astronauts on the moon. This implies that we will weigh differently on both places. For this reason, our weight will also vary on the various planets (because they are of different sizes). This is shown in the diagram below:
Weight depends on the degree at which the gravity on earth or moon or another planet pulls an object while the Mass of any object or body will always remain the same (constant) since it’s the amount or quantity of matter in the body.
We can escape earth’s gravitation pull by travelling far away from the earth into space. Since the space is somewhat empty and has no gravity, we will end up floating in it; because nothing attracts (pull) us in space. For this reason, astronauts will float in space as a result of a condition termed weightlessness.
Weightlessness results from a lack of gravity.
Note: It is not compulsory that the force of gravity must pull everything into contacting themselves. It can also bring objects close and not necessarily into contact. For instance the moon, sun, stars and other planets of the solar system does not make contact with the earth; rather, they have varying proximity to it as a result of gravity.
Other planets have their moons and they revolve around them. This is also a result of gravity that exists between these planets and their respective moons.
The scientists Sir Isaac Newton and Albert Einstein have been credited for their insight and explanations on gravity.
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Amazing facts in Physics
Image Credit: Ball and Roller Store
Glass Balls actually bounce higher than Rubber Balls
Every planet has its own unique gravitational force, for instance, Mars has a gravity of 3.711 m/s2 while earth’s gravitational force is 9.807m/s2. Please read on gravity here
When two metals are put together in space, they will stick together as if they are welded. This phenomenon is called cold welding
The fastest animal on land is Cheetah. It can reach a maximum speed of about 113km per hour.
Please read on motion, speed, velocity and acceeration here
NOTABLE POINTS IN Physics
The Classical Mechanics (Laws of Motion) is a fundamental part of Physics.
Below are the Newton's Laws of Motion:
An object at rest will continue in its state of rest; while an object in uniform motion will continue in a straight line, unless an external force acts on it.
Newton's First Law of Motion.
The rate of change of momemtum is proportional to the applied force and will take place in the direction of that force.
Newton's Second Law of Motion.
To every action, there is an equal and opposite reaction.
Newton's Third Law of Motion.
The study of Thermodynamics revolves around the relationship between heat, temperature, energy and mechanical work; and these can be summarised under the 4 laws of Thermodynamics (Numbered zero through three).
Below are the 4 laws of thermodynamics:
Zeroth law of thermodynamics – If two thermodynamic systems are each in thermal equilibrium with a third, then they are in thermal equilibrium with each other.
1st law of thermodynamics – Energy can neither be created nor destroyed but can be changed from one form to another.
2nd law of thermodynamics – The entropy of an isolated system not in equilibrium will tend to increase over time, approaching a maximum value at equilibrium.
3rd law of thermodynamics – As temperature approaches absolute zero, the entropy of a system approaches a constant minimum.
Fuses are present in many electrical devices. They are basically 🔥 fire-breakers 🔥
If there is a power surge, the fuse will break, preventing damage to the electrical devices. It will also prevent the incidence of 🔥 fire🔥 on/from such device.
Physics is one of the core sciences.
Physics is defined the scientific study of matter and the movement of matter through the space and time of the universe.
Understanding the basic and fundamental concepts of physics will help you better comprehend this subject. Below are some of the concepts: