Enhanced Science Reviewer Quarter 1 PDF

ENHANCED SCIENCE REVIEWER QUARTER 1 CHAPTER 1 INTRODUCTION TO FORCES AND MOTION Force (F) - referred as the push or pull - this is described in: 1. Magnitude - size or strength of the force (Newton or N) 2. Direction 3. Point of application 4. Line of action TYPES OF...

ENHANCED SCIENCE REVIEWER QUARTER 1 CHAPTER 1 INTRODUCTION TO FORCES AND MOTION Force (F) - referred as the push or pull - this is described in: 1. Magnitude - size or strength of the force (Newton or N) 2. Direction 3. Point of application 4. Line of action TYPES OF FORCES 1. Gravity Force - pull of a planet on an object - agent for the gravitational force: the entire planetel example: a leaf falling off a tree (the air pushing down the leaf is gravitational force) 2. Tension Force - contact force exerted by a string, rope, or wire on an object example: a person on a swing (the rope on the swing is exerting tension force) 3. Normal Force - the force exerted by a surface or agent against an object pressing against the surface - perpendicular to the surface example: book on a table (table pushing the book with normal force) 4. Friction Force - like normal, but it is always tangent to the surface BALANCE OF FORCES * If two forces acting on an object are equal in magnitude but opposite in direction, it is balanced forces and must lie along the same line * If an object is initially at rest under unbalanced forces, it moves in the direction of the unbalanced force COMBINING FORCES Fnet - vector sum of all forces acting on an object - two forces of equal magnitude and opposite direction will cancel out (unbalanced force) CHAPTER 2 FREE BODY DIAGRAMS - illustrates the relative magnitude and direction of all forces acting upon an object - the object must be isolated and “free” of its surroundings KEY TERMS: Newton (N) - unit of force in the metric system - equivalent to: kg m/s^2 Mass - the quantity of matter in a body Weight - measure of force of gravity on a body - varies depending on the location of the body in earth’s gravitational force - gravity’s acceleration: 9.8 m/s^2 - Formula for weight (m): m * g CHAPTER 3 THREE LAWS OF MOTION 1. Law of Inertia Inertia - the property to resist change - greater mass = greater inertia “a body will remain at rest or move at constant velocity unless acted upon by an external net or unbalanced force” 2. Law of Acceleration - the acceleration of an object is directly proportional to the magnitude of the net force - inversely proportional to its mass 3. Law of Interaction “for every action, there is equal and opposite reaction” CHAPTER 4 WORK - application of force through distance - method of transfer of energy - work is done on an object when the force covers a distance in the direction of the applied force: 1. Force 2. Displacement/Distance * same direction - when work is done by an object, it loses energy - when work is done on an object, it gains energy - the unit of work (Joule/J) is named after James Prescott Joule EXAMPLES OF WORK DONE * Work is done if the object pushed moves in the same direction as the force EXAMPLES OF NO WORK DONE * No work is done if the force you exert does not move the object * No work is done if the force you exert on the object does not move in the same direction you exerted CHAPTER 5 ENERGY - ability/capacity to do work 1. when work is done, energy is transferred 2. energy is transferred when work is done, not force Kinetic Energy - energy of motion - moving object - kinetikos: moving Potential Energy - stored energy of position possessed by an object TWO FORMS OF POTENTIAL ENERGY: A. Gravitational Potential Energy - energy stored in an object as a result of its vertical position or height - height can be measured relative to the assigned level - common reference level: the ground - higher/massive the object = greater PE B. Elastic Potential Energy - energy stored in elastic materials as a result of stretching/compressing - more stretch = more stored energy - if the string is not stretched/compressed ≠ no PE - string is said to be at equilibrium position CHAPTER 6 POWER - rate of doing work and using energy - the unit of power (Watt/W) is named after James Watt - watt is equivalent to 1 Joule / 1 Second CHAPTER 7 SOUND - sound is produced when a certain object is made to vibrate - an example of a longitudinal wave - needs a medium to propagate - sound is a mechanical wave CHARACTERISTICS OF SOUND WAVES 1. Wavelength - distance between adjacent identical parts of a sound wave 2. Amplitude - strength of sound waves 3. Frequency - associated with the sound’s pitch 4. Time Period - time taken to complete a vibration in a medium 5. Velocity - speed of sound travelled per unit of time SOUND TRAVELS BY: * the vibrations from an object set the particles in the air * the vibrations move from particle to particle * eventually reaches the ear Wave - periodic disturbance that moves away from a source and carries energy with it TWO TYPES OF WAVE: A. Longitudal Waves - waves that travel parallel to the motion of the particles B. Transverse Waves - movement of particles is perpendicular to the direction of the wave SPEED OF SOUND - affected by the elastic properties of the medium - strongest in solid - weakest in gas - temperature increases = speed increases - increase in sound speed in air is: 0.6 m/s per Celcius CHAPTER 8 LIGHT - electromagnetic wave between infrared & ultraviolet - form of energy made of photons (smallest unit of visible light) - 3x10^8 m/s - takes ≈8 minutes to reach Earth - dependent to the optical density - more dense medium = slower - less dess medium = faster - higher amplitude = brighter light - lower amplitude = dimmer light Electromagnetic Spectrum - electromagnetic waves are arranged in an increasing frequency ORDER OF THE ELECTROMAGNETIC SPECTRUM * radiowaves * microwaves * infrared * visible light spectrum (white light) * ultraviolet * x-rays * gamma CHARACTERISTICS OF LIGHT 1. Intensity - power of light - quantity that measures the amount of light illuminating a surface * Photometry - science of measuring the intensity or brightness of light 2. Brightnesss - visual perception in which light source appears to be emitting light or a surface to be reflecting light 3. Luminous Intensity - amount of light that the objects produce * Candela - measuring of the amount of light 4. Color - depends on the frequency or wavelength of the radiation that reaches the eye * White - combination of all the wavelengths of visible light * Black - absence of the wavelengths Refraction - bending of light when it travels to another medium with different optical densities Apparent Depth - illusion that the objects under water appear nearer to the surface Dispersion - special kind of refraction - seperation of white light into different colors Red * least refractive index * least bent * topmost * least energy * lowest frequency * highest wavelength Violet * greatest refractive index * most bent * bottom * most energy * highest frequency * lowest wavelength CHAPTER 9 HEAT AND TEMPERATURE Heat - transfer of energy between objects due to temperature difference - higher temperature to lower temperature - greater mass = more heat can be transferred - measured in Joules Specific Heat Capacity - measure of the amount of energy needed to change an object’s temperature Heat Capacity - amount of heat needed to raise a substance’s temperature to 1-degree celcius - dependent to the mass of an object Temperature - amount of heat in an object - man-made indicating where heat is flowing - measured in Celcius Calorimeter - object used to measure the heat Thermal Expansion - materials expand when heated - materials retract when cooled Thermometer - a device that measures temperature Phase Change - occurs when heat is added or taken out of an object TEMPERATURE SCENARIO * while ice is melting, the temperature remains the same * a change in temperature = change in kinetic energy * after the ice melts, the temperature rises with time RELATIONSHIP BETWEEN HEAT AND TEMPERATURE * when heat is going to the system, the temperature rises * when heat is leaving the system, the temperature decreases CHAPTER 10 CURRENT, VOLTAGE, RESISTANCE 1. Current - also known as "electric current" - number of electrical charges - symbol: I - unit: Ampere (A) — Andre-Marie Ampere TYPES OF CURRENT FLOW A. Conventional Current Flow - positive to negative (+ to -) B. Electron Current Flow - negative to positive (- to +) Ammeter - used to measure electric current 2. Voltage - measure of amount of energy to electrons to move them - causes the current to flow - symbol: V - unit: Volts (V) — Alessandro Volta * voltaic pile/dry cell - forerunner, sealed container that holds chemicals that produce electricity Voltmeter - used to measure voltage RELATIONSHIP BETWEEN CURRENT AND VOLTAGE * voltage increases = current increases 3. Resistance - hindrance to the movement and flow of electrical charges - symbol: R - Unit: Ohms (Ω) — George Simon Ohm RELATIONSHIP BETWEEN RESISTANCE AND CURRENT * resistance increases = current decreases * lower resistance = bigger current * conductors: low resistance, allowing more current * insulators: high resistance, less current * longer wire: high resistance * thicker wire: low resistance CHAPTER 11 SERIES AND PARALLEL CIRCUITS Circuit - path along where electrical charges flow TYPES OF CIRCUIT 1. Series Circuit - connected to a single pathway - gap/break stops flow of current = no current passes 2. Parallel Circuit - connected to form branches - each has a separate pathway - gap/break = no effect to other branches Current Rating - current a wire given that the diameter can carry - overload of a circuit: current in the circuit exceeds current rating Octopus Wiring - too many appliances plugged in a single outlet Short Circuit - exposed parts of electrical wires touch one another HOW SHORT WIRES RESULT TO FIRE: * low resistance * current rapidly increases * overloading of circuit WHY WIRES HEAT UP WHEN THERE IS TOO MUCH CURRENT: * electrons collide with atoms * higher kinetic energy * higher temperature Circuit Breaker - automatic device that automatically stops the flow of current Fuse - electrical safety device built designed to melt and separate in case of excessive current Double insulation - used so that the wire will not contact its outer casing Earthing - known as "grounding system" - connects specific parts of an installation to Earth’s conductive surface