Physics Fundamentals Overview

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Questions and Answers

What is the defining characteristic of a compound?

It contains only a single type of atom.

It can only be formed from non-metal elements.

It is made up of identical molecules comprised of different atoms in exact proportions. (correct)

It consists of different atoms in varying proportions.

Which of the following compounds is formed from the combination of hydrogen and oxygen?

Carbon dioxide (CO2)

Methane (CH4)

Sodium chloride (NaCl)

Water (H2O) (correct)

What occurs during chemical bonding to form a compound?

Atoms change their atomic number.

Atoms lose all their electrons.

Atoms repel each other.

Atoms share or transfer electrons. (correct)

Which statement is true regarding the properties of compounds compared to their individual elements?

Compounds typically have completely different characteristics from their constituent elements. Signup and view all the answers

In the molecule of water (H2O), how many hydrogen atoms bond with one oxygen atom?

Two hydrogen atoms bond with one oxygen atom. Signup and view all the answers

Which state of matter is characterized by a definite shape and volume?

Solid Signup and view all the answers

What is the process called when a solid turns into a gas without becoming a liquid first?

Sublimation Signup and view all the answers

Which of the following statements correctly describes the center of gravity?

It is the point where the mass of a body is concentrated. Signup and view all the answers

Which concept explains the resistance of a material to deformation under tension?

Elasticity Signup and view all the answers

In static equilibrium, what condition must the sum of the forces and moments acting on an object satisfy?

Both must equal zero. Signup and view all the answers

When a liquid is subjected to pressure, which principle can be used to describe its behavior?

Pascal's principle Signup and view all the answers

Which of the following describes a chemical compound?

A substance formed by the combination of two or more elements. Signup and view all the answers

What term is used to describe the change in state from gas to solid?

Deposition Signup and view all the answers

What type of stress develops in the direction opposite to a twist applied to a rod fixed at one end?

Tension stress Signup and view all the answers

What phenomenon often leads to failures in components despite low externally applied stress levels?

Residual Stress Signup and view all the answers

Which statement correctly describes the properties of fluids?

Liquids are considered incompressible, while gases are compressible. Signup and view all the answers

What causes a crack to originate in a material experiencing torsional stress?

Point of highest tensile stress Signup and view all the answers

How can residual stress be beneficial in applications such as car windscreens?

It helps mitigate impacts during accidents. Signup and view all the answers

What happens to the molecular movement of solid matter when heat energy is added?

It increases. Signup and view all the answers

What is the primary characteristic of liquids regarding their volume and shape?

Liquids have a definite volume but no definite shape. Signup and view all the answers

Which force is responsible for preventing liquids from expanding freely?

Surface tension Signup and view all the answers

What occurs when heat energy causes a liquid to reach a point where surface tension can no longer hold its molecules?

The liquid evaporates into gas. Signup and view all the answers

Which statement about the compressibility of liquids is correct?

Liquids are incompressible. Signup and view all the answers

What can influence the amount of heat required to change a liquid to a gas?

The type of liquid Signup and view all the answers

What happens to the volume of a material when it changes from a solid to a liquid?

The volume does not significantly change. Signup and view all the answers

Which of the following best describes the distance between molecules in a liquid compared to a solid?

Molecules in a liquid are farther apart than those in a solid. Signup and view all the answers

What does gauge pressure measure?

Pressure above or below atmospheric pressure Signup and view all the answers

At sea level, what is the typical atmospheric pressure?

14.7 psi Signup and view all the answers

What is meant by absolute pressure?

Line pressure adjusted for atmospheric pressure Signup and view all the answers

Why do modern aircraft maintain a cabin altitude equivalent to 8000’?

For passenger comfort Signup and view all the answers

What is the relationship between altitude and atmospheric pressure?

Atmospheric pressure decreases as altitude increases Signup and view all the answers

What type of pressure is displayed by tire pressure gauges?

Gauge pressure Signup and view all the answers

What happens to atmospheric pressure as the number of air molecules above an area increases?

It increases due to greater weight Signup and view all the answers

What does a differential pressure gauge measure?

The difference in pressure between two points Signup and view all the answers

Study Notes

What is Physics

Physics is the study of the universe, energy, matter, and their interactions.
Topics include density, time, motion, pressure, electricity, and ambient conditions.

Matter

Matter is composed of chemicals that combine to form a variety of substances known as compounds.
There are 109 known elements; compounds consist of molecules made from these elements.
Examples of compounds include water (H2O), carbon dioxide (CO2), and sodium chloride (NaCl).
Molecules in a compound are identical and composed of different atoms in specific proportions.

States of Matter

Solids

Solids have a definite shape and volume.
Molecules in solids are tightly packed and have limited movement.

Liquids

Liquids have definite volume but no fixed shape; they conform to their container.
When transitioning from solid to liquid, molecular movement increases but volume remains largely the same.
Liquids are incompressible and maintain partial bonding known as surface tension.

Gases

In gases, molecules move freely and are far apart; they can expand to fill any container.
The transition from liquid to gas occurs when sufficient heat energy overcomes surface tension, allowing molecules to escape into vapor.

Mechanical Concepts

Forces, moments, and couples interact in systems, represented as vectors.
Mechanical advantage can be demonstrated with simple machines.
Centre of gravity is critical in analyzing stability.
Stress types include tension, compression, shear, and torsion.

Pressure and Buoyancy

Pressure in fluids increases with depth and is dependent on area.
Liquids are incompressible with constant density; gases are compressible.
Buoyancy is the upward force experienced by objects submerged in a fluid.

Measurement of Pressure

Atmospheric pressure at sea level is approximately 14.7 psi.
Pressure gauges measure different types of pressure:
- Gauge pressure: pressure relative to atmospheric pressure.
- Absolute pressure: total pressure, including atmospheric.
In aviation, cabin pressure is maintained at an altitude equivalent to 8000 feet (approximately 11 psi) for passenger comfort.

Residual Stress

Internal stresses arise from abrupt temperature changes during processes like heat treatment.
Residual stress can be beneficial as in controlled crazing in car windshields, ensuring safer performance during impacts.

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Description

This quiz focuses on the foundational concepts in physics, exploring topics such as the universe and the fundamental principles that govern physical phenomena. Completing this quiz will enhance your understanding of what physics encompasses and its relevance to engineering. Perfect for students entering the field of engineering.