Physics Flashcards
What is a scalar quantity?
A quantity that is fully described by a magnitude (or numerical value) alone.
E.g. length, time, mass volume, density, power, pressure, energy
What is a vector quantity?
a quantity that is fully described by both a magnitude and a direction.
E.g. weight, force
What is distance?
A scalar quantity that refers to “how much ground an object has covered” during its motion.
What is displacement?
A vector quantity that refers to “how far out of place an object is”; it is the object’s overall change in position.
What is speed?
A scalar quantity that refers to “how fast an object is moving”.
What is velocity?
A vector quantity that refers to “the rate at which an object changes its position”.
What is acceleration?
A vector quantity that refers to “the rate at which an object changes its velocity”.
What is a physical quantity?
A property of an object that can be measured with a measuring instrument. Usually expressed as “a magnitude (numerical value) and a physical unit or more”.
What is the formula for force?
mass x acceleration
What are the equipment and units for length?
ruler, tape wheel
meters (m)
What are the equipment and units for time?
stopwatch
seconds
What are the equipment and units for volume?
measuring tube
cm3, m3, or dm3
What are the units for speed and velocity?
m/s
meters/second
What is mass?
The amount of matter in something.
kg
What is weight?
The effect of gravity on a mass.
Newtons (N)
What is density?
The amount of mass in a given volume.
density = mass/volume
measured in g/cm3 or kg/m3
What are all forces measured in?
Newtons
What is the formula for pressure?
Force/Area
measured in pascals (Pa) or N/m2
How do you measure mass?
A top-pan balance.
What is a force?
A push, pull, or twist that can change something about an object.
It can change the object’s speed, direction, or shape.
What are the contact forces?
Friction, normal, applied, air/water resistance, tension, compression.
What are the non-contact forces?
Gravity, electrostatic, magnetic.
What is Newton’s first law of motion?
An object stays at rest or continues to move at a constant speed in a straight line unless a net (resultant) force acts on it.
What is acceleration measured in?
m/s2
How do you find the distance on a speed-time graph?
Measure the area under the graph.
What is the equation for speed?
distance/time
What is a moment?
The turning effect of a force.
What is the equation for a moment?
force x distance (from the pivot)
How do you find the centre of gravity in a regular shape?
Draw lines from the corners of the shape. It’s where they meet.
What is the law for the conservation of energy?
Energy cannot be created or destroyed, only transferred from one type into another.
What are the four energy pathways?
Mechanical
Electrical
Heating
Radiation
What is the mechanical energy pathway?
A force moving an object through a distance.
What is the electrical energy pathway?
Charges moving due to a potential difference.
What is the heating energy pathway?
Temperature difference caused by an electrical or chemical reaction.
What is the radiation energy pathway?
Energy transferred as a wave.
What are the nine types of energy?
Heat/thermal, light, sound, gravitational potential, chemical, elastic potential, nuclear, kinetic, and electrical.
What is energy measured in?
Joules (J).
What is work done?
The quantity of energy transferred by the force to move an object.
What is the formula for work done?
Force x distance
What is power?
How much energy we get per second.
What is the formula for power?
Energy/time
or
Work done/time
Measured in Watts
What is the formula for kinetic energy?
1/2mass x velocity2
1/2mv2
What is the formula for gravitational potential energy?
mass x gravity x height
What is the efficiency equation?
useful energy output/total input
What are three differences between boiling and evaporation?
Boiling is quick and evaporation is slow.
Boiling occurs at a single temperature and evaporation can occur at various temperatures.
Boiling takes place throughout the liquid and evaporation takes place only at liquid surfaces.
What is the formula for pressure changes?
P1V1= P2V2
pressure1 x volume 1 = pressure2 x volume2
What is the kinetic molecular model of matter?
Solids only vibrate and stay in fixed positions and have strong intermolecular attractions.
Liquids can move freely around each other and have weaker intermolecular attractions.
Gases move freely and have weak intermolecular attractions.
What is sensitivity related to thermometers?
The ability if a thermometer to detect small changes in temperature.
What is range related to thermometers?
The range of temperatures which can be measured by the thermometer.
What is linearity related to thermometers?
The expansion of the liquid should be linear for all different temperatures.
How does increasing the bulb size of a thermometer affect its range and sensitivity?
The thermometer has a shorter range and is more sensitive.
How does increasing the bore diameter of a thermometer affect its range and sensitivity?
The thermometer has a longer range and is less sensitive.
How does increasing the stem length of a thermometer affect its range and sensitivity?
The thermometer has a longer range and no change to sensitivity.
What is temperature?
The average amount of energy per particle.
What are some good conductors?
Metals (copper, tin, iron, aluminium, magnesium)
What are some good insulators?
Plastic, leather, cottor, silicon, paper, wood
What are convection currents?
When less dense water/air rises (when heated) and more dense water/air sinks (when cooled) in circles in fluids.
What are the three things thermal radiation can do when it falls on an object?
Be absorbed, transmitted or reflected.
What is the order of colours from best emitters/absorbers to worst emitters/absorbers?
Dull black - Worst reflector
Shiny black
White
Silver - Best reflector
What happens to the temperature of an object if the average energy radiated is more than is absorbed?
The temperature falls.
What is the formula for voltage?
V=IR
Voltage = Current x Resistance
What is the formula for charge?
Q=IT
Charge = Current x Time
What is the formula for power?
P=IV
Power = Current x Voltage
What is the formula for energy?
E=VIT
Energy = Voltage x Current x Time
How do you find the total resistance in a series circuit?
R1 + R2 = Rtotal
How do you find the total resistance in a parallel circuit?
1/R1 + 1/R2 = 1/Rtotal
Rearrange the equation
