Physical Science Q2 Exam Flashcards
Machines decrease the amount of energy that is needed to do work. T/F?
false
Because of friction, using machines increases the amount of energy that is needed to do work. T/F?
true
What is the difference between work and power?
work = force applied through a distancepower = the rate at which work is done
What is the unit for work?
joules
What is the unit for power?
watts
What is the difference between kinetic and potential energy?
potential energy is stored energykinetic energy is energy of motion
Gravitational potential energy depends on the _______?
height
Sound waves are compression/transverse waves.
compression
The frequency of a sound wave determines:
pitch
How loud a sound is depends on:
amplitude
Define resonance:
the reinforcing of an object’s natural frequency so that the amplitude increases quickly–or–when the vibration of one object causes another to vibrate at natural frequencies
A sonar system measures distance by determining the…
time it takes for sound waves to be reflected from a surface
The color of light is determined by the _______ of the light waves.
frequency
Which type of electromagnetic wave has the greatest wavelength?
radio waves
When light rays reflect off a rough surface, they…
scatter in many different directions
An image that results from an apparent path of light rays is called
virtual
Light rays that pass through a lens change direction because…
they are refracted
There is a repulsive force between two charged objects when…
they have the same charge
There is an attractive force between two charged objects when
they are opposites
When there is an equal amount of positive or negative charges on an object, the object is…
neutral
When a glass rod is rubbed with silk and becomes positively charged, …
the silk becomes negatively charged
The electric force between charged objects is…
proportional to size & inversely proportional to distance
Electric force varies depending on the…
charge & distance
Current is the rate at which charges move through a(n):
conductor
The unit of resistance is:
ohms
Whether or not charges will move in a material depends partly on how tightly _____ are held in the atoms of the material.
electrons
Appliances connected so that they form a single pathway for charges to flow are connected in a(n):
series circuit
A device that protects a circuit from current overload is called a(n):
fuse
What is energy?
the ability to do work
What is work?
force applied through a distance
What is the formula for work?
w = Fd
What is the unit for work?
joules
What 2 things will affect the amount of work done?
force & distance
What is power?
the rate at which work is done
What is the formula for power?
p = w/t
What is the unit for power?
watts
What are the different forms of energy?
thermalchemicalnuclearsoundlightmechanical (kinetic & potential)electrical
What is the law of conservation of energy?
energy cannot be created or destroyed
Energy transformations:Boy eating an apple then walking to work.
chemical -> mechanical
Energy transformations:Gasoline in your car used to drive.
chemical -> mechanical
Energy transformations:Turning on a light.
electrical -> light
Energy transformations:Hair dryer being turned on.
electrical -> thermal
If 2 people collide the amount of energy before the collision is more/less/the same as after the collision.
the same
The amount of potential energy at the top of a roller coaster hill is slightly larger than the kinetic energy at the bottom of the hill. Why is this?
some energy is lost as heat because of friction
What is kinetic energy?
energy of motion
What is the formula for kinetic energy?
ke = 1/2(m)v^2
What is the unit for kinetic energy?
joules
What is potential energy?
stored energy
What is the formula for potential energy?
pe = mgh
What is the unit for potential energy?
joules
What is a medium?
the material through which a wave travels
Electromagnetic waves are fastest in what medium?
vaccums
What type of wave is a sound wave?
longitudinal/compression
Do light waves have mass?
NO
Do sound waves have mass?
NO
What type of wave is a light wave?
transverse
What type of waves are electromagnetic waves?
radiomicroinfraredvisible lightultravioletxraygamma
What is the formula for wave speed, wavelength, and frequency?
V = λf
What is the unit for wave speed?
m/s
What is the unit for wavelength?
m(eters)
What is the unit for frequency?
h(ert)z
What is it called when a wave bends as it goes from one medium to another?
refraction
Order the electromagnetic spectrum from longest to shortest wavelength.
radiomicroinfraredvisible lightultravioletxraygamma
What electromagnetic wave has the least energy?
radio
What electromagnetic wave has the most energy?
gamma
What is the difference between period and frequency?
period - time for one cyclefrequency - cycles in one second
What is the formula for period?
p = 1/f
What is the formula for frequency?
f = 1/p
What is the unit for period?
seconds
What type of EM radiation is used to fight cancer?
gamma rays
What type of waves do ultrasounds use?
sound waves
What type of wave is harmful to our skin but also beneficial in small amounts?
ultraviolet
What is the Doppler effect?
the increase in the frequency of sound or light as the source and observer get closer to each other
Will sound intensity increase or decrease as you move closer to the noise?
increase
What is an echo?
reflected sound
What is reflection?
when a wave bounces off a hard boundary
Why do see lightning before we hear thunder?
light travels faster than sound
What is current?
moving electrons/charge
What is voltage?
how much work a battery can dopushes electricity through a circuit
What is resistance?
slows down the flow of electricity
What is the formula for current, voltage, and resistance?
I = V/R
What is the unit for current?
amps
What is the unit for voltage?
volts
What is static electricity?
a buildup of charge on an object
What is absorption?
a wave’s energy dies out in a soft material
What is damping?
the process of harmonic motion losing amplitude over time
What is a phase?
a particular part of a cycle
Define in-phase:
when 2 waves are at the same part of their cycles
Define out-of-phase:
when 2 waves are at different parts of their cycles
What is constructive interference?
when 2 waves combine to create a larger wave with greater amplitude
What is destructive interference?
when 2 waves combine to create a smaller wave with smaller amplitude
What is diffraction?
when a wave bends around a corner
What is refraction?
when a wave bends when entering a transparent boundary
What is natural frequency?
the frequency at which an object vibrates at when disturbed
A light wave’s brightness is determined by:
amplitude
Define infrasonic:
a sound too low to hear
Define ultrasonic:
sound too high to hear
Define supersonic:
motion faster than sound
What is a sonic boom?
caused by an object breaking the sound barrier
What is Coulomb’s law?
the force between 2 charged particles varies directly as the product of the magnitude of their charges and inversely as the square of the distance between them
What is the formula for calculating the electric attraction between two things?
f= kq1q2/d^2(f - forcek - proportionality constantq - charged - distance)
