SCIENCE 4TH QUARTER REVIEW

• Refers to a change in position of a body

  Motion
• Is any point in space used for comparison to determine whether a body is in motion or not.

  Reference point
• Is the actual length traveled by a body

  Distance
• Is the shortest straight-line distance from the initial position to the final position of a body

  Displacement
• This symbol represents a change between two quantities.

  Delta
• This describes how fast a body moves is to measure the distance it travels in a given time interval

  Speed
• The speed of a moving body at a particular instant of time or point along its path

  Instantaneous speed
• Is the velocity at a particular instant of time or point along a path

  Instantaneous velocity
• Is defined as the rate of change of velocity

  Acceleration
• Means that the velocity of the body changes at a constant rate

  Uniformly accelerated motion
• A falling body that is free from air resistance and that falls under the influence of gravity alone

  Free fall
• Is the force exerted by air on a body that resists the body's motion

  Air resistance
• It moves downward with a constant velocity

  Terminal velocity
• Is a device that detects physical movement within a distance and converts the motion into an electrical signal

  Motion detector
• Are widely used for automatic door openers and security alarms

  Ultrasonic motion detectors
• Are used for fire or smoke detection

  Infrared detectors
• Are widely applied in automatic lighting systems, toilet flushers, and speed measurement

  Radar-based motion detectors
• Detects the presence of any infrared-emitting source, such as humans

  Passive infrared motion sensor
• Is a disturbance that moves from one place to another

  Wave
• The substance that transfers the energy, or light from one substance to another substance

  Medium
• Is a single disturbance

  Wave pulse
• Is a series of disturbances

  Wave train
• The direction of motion of the particles of the medium is perpendicular to the direction of propagation of the wave

  Transverse wave
• The highest point of a transverse wave

  Crest
• The lowest point of a transverse wave

  Trough
• The maximum displacement from the equilibrium position

  Amplitude
• The middle position of a transverse wave

  Equilibrium
• Particles that are in the same direction of motion and have the same displacement

  Phase
• The distance between two successive wave particles that are in phase

  Wavelength of a transverse wave
• A wave that travels in a direction parallel to the direction of motion of the particles of the medium

  Longitudinal wave
• Is a region where the particles are pressed together

  Compression
• Between successive compressions is a stretched region

  Rarefaction
• Waves that require a medium

  Mechanical waves
• Waves that don't need a medium to travel

  Light waves
• Is an electromagnetic wave

  Light
• Propagate with or without a medium

  Electromagnetic waves
• Is the number of waves passing through a given point per unit of time.

  Frequency
• Is the distance traveled by a wave per unit of time

  Wave speed
• Are longitudinal waves produced by vibrating bodies.

  Sounds
• The human voice is produced by the vibration of membranes in the throat

  Vocal cords