forces exam (November)

Created by

Chesca durston

Cards (47)

Name as many energy stores as you can
kinetic
chemical
elastic potential
thermal
light
magnetic
nuclear
gravitational potential
electrostatic
give an example of kinetic energy in everyday life 
ball rolling down a hill (moving things)
Give an example of chemical energy in everyday life 
batteries, food, fuel
gives examples of elastic potential, internal, light, magnetic and gravitational potential, nuclear and electrostatic energy in everyday life
elastic potential - springs
internal - heating water for a bath
light - candles, lightbulbs
magnetic - blender, washing machine
gravitational potential - a car parked at the top of a hill
nuclear - space exploration
electrostatic - laser printers, photocopiers
energy is measured in ...? 
J - joules
energy changes in... 
systems
the amount of substance in an object is the what? 
mass - measured in Kg
the gravitational pull on an object is the what? 
weight - measured in N
what is the equation for weight? 
$w =$ $mg$
w = weight
m = mass
g = gravitational field strength
what is gravitational potential energy? 
the energy because something has changed height / fallen
Gravitational potential of an object depends on: 
How high up an object is
The mass of the object
The gravitational field strength
What is the equation for gravitational potential energy? 
$Ep =$ $mgh$
Ep = gravitational potential energy
M = mass
G = gravity
H = height
a book of mass 0.15Kg is lifted 0.6m from one shelf to another. Calculate the gravitational potential energy gained by the book
0.15 x 9.8 x 0.6 =0.882
What is kinetic energy? 
the energy of a moving object
measured in J
Kinetic energy depends on: 
mass of the object
velocity of the object
what is the equation for kinetic energy? 
$Ek =$ $1/2mv*$ $2$
Ek = kinetic energy
M = mass
V = velocity is
When an object falls all the gravitational potential energy is transferred into kinetic energy
Energy can’t be destroyed or created only transferred
What is elastic potential energy? 
the energy in anything that is squashed or stretched
What is the equations for elastic potential energy? 
$Ep =$ $1/2ke*$ $2$
Ep = elastic potential energy
M = spring constant
E*2 = extension
what is power  
The energy transferred in one second
measured in W
what is the equation for power? 
P = W /T
P = power
W = work done
T = time
what does efficiency tell us?  
what fraction of the energy supplied is transformed usefully
What is the equation for efficiency? 
efficiency = useful energy output / total energy input
what is the independent variable?  
the thing you change
what is the dependent variable? 
The thing you measure
What is the control variable 
The thing you keep the same
Method for the required practical  
the method :
name as many energy resources as you can 
solar
nuclear
fossil fuels
geothermal
wind
wave
biofuels
tidal
kinetic
hydroelectric
Energy resources can be : 
renewable ( ones that never run out ) or non-renewable (ones the will run out)
give an example of a non - renewable energy resource and a renewable energy resource
non -renewable = fossil fuels
renewables = solar panels, wind turbines
give the positives of wave energy 
renewable
no pollution
give the negatives of wave energy  
costs a lot of money
Looks ugly
Can be damaged by storms
Needs lots of machines
Give the positives of solar energy  
Renewable
No pollution
Give the negatives of solar energy  
Solar cells/ panels are expensive
Only work at night
give the positives of wind energy 
renewable
No pollution
Turbines are cheap and easy to build
can be used in poor countries
give the negatives of wind energy 
Ugly & noisy
Only work when it’s windy
give the positives of hydroelectric energy 
renewable
no pollution
can store water up high and then let it out when energy is needed
Give the negatives of hydroelectric energy 
Costs lots of money to build a dam
can ruin local environment
Give the positives of tidal energy 
Renewable
No pollution
Reliable as there is always 2 tides a day
cheap to run once it’s built