Study Guide

# Physics Basics Questions

## Physics Basics Questions

What exactly is physics and what topics does it cover?
What is the fundamental difference between the study of forces and the study of motion?
What is the difference between displacement, velocity, and acceleration?
What are some examples of forces?
How are electricity and magnetism related?
What is thermodynamics?
How are waves and optics related?
How can there only be seven SI units, when physics uses dozens of units?
When completing a physics experiment, how is the data usually presented?
What is experimental error, and what are the different types?

What exactly is physics and what topics does it cover?

Physics is a science that attempts to come up with basic laws and rules that explain the entire universe, from the tiny to the huge. Since it covers the whole universe, it has a lot of topics within it, including: forces, motion, rotation, energy, electricity, waves, heat, engines, fluids, waves (including light and sound), optics, subatomic particles, astronomy, and aeronautics.

What is the fundamental difference between the study of forces and the study of motion?

The study of motion involves understanding and describing how things move, using equations and graphs, without any reference to what causes that motion. The study of forces tells us why things move, or why motion changes – based on the forces (pushes and pulls) on an object.

What is the difference between displacement, velocity, and acceleration?

Displacement is the change in position of an object over time. Velocity is the rate at which that position changes (the number of meters the position of an object changes every second). The more rapidly the position of an object changes, the greater its velocity must be. Acceleration is the rate at which anobject’s velocity changes (the number of meters per second the velocity of an object changes by each second). The more rapidly the velocity of an object changes, the greater its acceleration must be.

What are some examples of forces?

There are many examples of forces, including gravity (weight), friction, tension, reaction (normal) forces, magnetic forces, electric forces, buoyancy, lift, drag (air resistance), and thrust/driving forces.

How are electricity and magnetism related?

Electricity is generated in power plants using large magnets, by causing a loop of wire to turn inside a magnetic field. So without magnetism, electricity wouldn’t exist. Magnets are also used in many electrical devices like microphones (turning sound waves into electricity) and speakers (turning electricity into sound waves).

On a more fundamental level though, electricity and magnetism are really part of one larger, fundamental force called the electromagnetic force. So the real reason is that they are related is that they’re two sides of the same coin.

What are the laws of thermodynamics?

Thermodynamics is the study of the movement (dynamics) of heat (thermal energy). The laws of thermodynamics are rules that explain how heat moves and acts in the natural world. The first law of thermodynamics includes the fact that heat only naturally moves from hot places to cold places. The second law of thermodynamics explains that the universe as a whole will only get more disorderly with time, and any process we complete makes it more disorderly when we look at the big picture.

How are waves and optics related?

Waves is the study of vibrations in space and time which carry energy. There are many types of waves including sound waves, water waves, seismic waves, and light waves. Optics is the study of one of these types of waves: light waves. Light waves need their own area of study because they have features that are different to other kinds of waves. Light waves of vibrations in electric and magnetic fields, and can travel through the vacuum of space – they can move without a physical material or medium.

How can there only be seven SI units, when physics uses dozens of units?

Although physics uses many different units, all of those units are combinations of the same seven basic SI units. There’s nothing wrong with using joules as the unit of energy, as long as we know that it is really a newton meter. (And a newton is really a meter-kilogram-per-second-squared.)

When completing a physics experiment, how is the data usually presented?

Data from physics experiments are usually plotted on scatter graphs, with the independent variable on the x-axis, and the dependent variable on the Y axis. A line of best fit which best represents the data is then drawn through the scatter plot. That line can be straight or curved.

What is experimental error, and what are the different types?

Experimental error is the uncertainty in the data from an experiment. This uncertainty can come from several sources, and each is regarded as a different type of experimental error. Instrument error describes the limitations of the instruments we are using to collect data, like the fact that the weighing scale may only measure to the nearest hundredth of a kilogram. Random error describes the way our measurements will sometimes vary around the true value, like when measuring something with a stopwatch, where we get some measurements that are larger than the true value, and some measurements which are smaller than the true value. Last of all, systematic error is where our measurements are all out by the same amount, like if our scale wasn’t calibrated correctly. Human error, or mistakes, are not an example of experimental error – they should be fixed while the experiment is being completed.

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