Physics: Light, Lenses, Wind, Motion, and Radiation
Physics: Understanding the Physical World
Light and Its Properties
Light is a form of energy that enables us to see.
- Luminous objects emit their own light. Example: Fire
- Non-luminous objects do not emit their own light but reflect light. Example: Table
Mirrors and Their Effects on Images
- Convex mirrors make images appear smaller.
- Concave mirrors make images appear larger.
- Plane mirrors produce no change in image size.
Experiment: Image Formation in a Plane Mirror
Set up the equipment as shown in the diagram.
Read MoreElectric Fields and Magnetic Phenomena: Understanding the Basics
Lines of Force
Lines of force are imaginary lines that mark the path a positive charge would follow if left free in an electric field. These lines must meet the following conditions:
- Lines emerge from positive charges (sources) and enter negative charges (sinks).
- The number of lines entering or leaving a point charge is proportional to the value of the charge.
- At each point in the field, the number of lines per unit area perpendicular to them is proportional to the field strength.
- Two lines of force
Physics Problems: Motion, Force, and Energy Solutions
Understanding Linear Motion with Constant Acceleration
1. A truck starts from rest and moves with an acceleration of 4 m/s2. Find its velocity and the distance traveled after 15 seconds.
- Xf = Xi + Vit + at2/2
- Vf = Vi + at
Since the truck starts from rest, Xi = 0 and Vi = 0.
- Xf = at2/2
- Vf = at
- Xf = (4)(15)2/2
- Vf = (4)(15)
- Xf = 450 m
- Vf = 60 m/s
Calculating Deceleration and Force in Linear Motion
2. A car of mass 1,200 kg, traveling at 25 m/s, stops completely in 6 seconds. What is the value of the acceleration
Read MoreFundamental Laws of Physics: Thermodynamics, Mechanics, Waves
Fundamental Laws of Physics
Zeroth Law of Thermodynamics
If two systems are in thermal equilibrium with a third, they are in thermal equilibrium with each other.
First Law of Thermodynamics
Heat supplied to a system increases its internal energy and does work.
Second Law (Kelvin-Planck Statement)
No process can solely convert heat from a reservoir into work.
Clausius Statement
No process can solely transfer heat from a colder to a hotter object.
Newton’s Law of Cooling
The rate of cooling is proportional
Read MoreUnderstanding Electric Fields: Properties, Laws, and Potential
The Electric Field
1. Properties of Electric Charges
- Point load: dimensionless electrical body.
- There are 2 kinds of charges in nature:
- Positives: load acquired by the glass rubbed. Carry this burden of protons.
- Negative: is the burden becomes amber, and carry it with electrons.
- The charges repel and attract opposite sign.
- The charge is conserved. In the electrification charge is not created, only passed a few bodies to others, so that the total charge remains constant.
- The charge is quantized. It is represented
Sound Transmission and Properties: Acoustics and Reflection
Sound Transmission and Properties
Media that Transmit Sound
The sounds we hear are typically transmitted through the air. However, any elastic substance, whether solid, liquid, gas, or plasma, can transmit sound.
Elasticity is the property of a material that allows it to change shape in response to an applied force and return to its original shape when the force is removed. Steel is an elastic substance, while putty is inelastic. In liquids and elastic solids, molecules are relatively close to each
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