P4 - explaining motion Flashcards
What is a contact force
A force where the two objects need to be touching, e.g pushing a chain
What are non contact forces
A force where the two objects do not need to touch, e.g the sun gravitational pull
What is the measure for mass
Kg
What direction is weight
Towards the centre of mass
What is the formula for weight
Weight = mass * gravitational field strength
What is the GFS on earth (for the sake of GCSE)
10 N/Kg
Is displacement scalar or vector
vector
How do u convert km/h to m/s
divide km/h by 3.6
formula for acceleration
acceleration = (change in speed)/time
equation for constant acceleration
v^2 = u^2 + 2as
what is v
final speed
what is u
start speed
what is s
distance
On a distance time graph, what does the gradient show
the average speed of the object
On a velocity time graph, what does the gradient show
acceleration
what does a flat line on a velocity time graph show
constant speed
What does the area under the line on a velocity time graph show
distance travelled
What must you always add to a resultant force
direction EVEN if at an angle, calculate the agnle
What is centripetal force
The force that stops the object flying away
What causes the centripetal force in a ball being spun on a rope
the tension in the rope
What causes the centripetal force in a moon orbiting the earth
The gravitational force from the earth
Equation for momentum
momentum = mass x velocity
What causes the centripetal force in a wooden block on a spinning table
The friction of the block
Formula for change in momentum
Change in momentum (kg m/s) = resultant force x time for which it acts
what is the conservation of momentum
momentum before = momentum afterwards
Which gear move faster, the small or the big one
The small one
What is stopping distance?
Thinking distance + braking distance
Formula for work done e.g pushing a wheelchair up a hill
Work = force x distance
Formula for KE
KE = 1/2 x m x v^2
Formula for power (mechanical)
energy transferred / time
how much is one joule (in work done)
one newton metre
what is the typical speed of a plane
900 km/h
Formula for GDP
mass x GFS x height
Is acceleration scalar or vector
vector
What is the equation for resultant force
F = ma
units for work done
Joules
Formula for power
Power = work done/ time
What is power measured in
Watts
Formula for change in momentum
Change in momentum = force x time
Euqation for momentum linking mass and velocity
Mass x velocity
Formula for force
change in momentum / time
What is the unit for momentum
kgm/s
What is the law for conservation of energy
Cannot be created or destroyed, only transferred
What are the 8 energy stores
MAGNETIC
ELECTROSTATIC
ELASTIC
gravitational potential
nuclear
kinetic
thermal
chemical
What is a system in physics
A collection of matter, when concerned with their energy levels
What is a open system
A system where energy can be transferred to the outside environment
What is a closed system
A system where neither matter or energy can enter or exit
formula for kinetic energy
1/2 mv^2
Formula for work done
Work done = Force x Distance
W = fd
What is the measure of power
Watts
What is the measure of energy
Joules
What is the measure of work done
Joules
Formula for power
Power = Energy (transferred) / time
P=E/t
x10^3
Kilo
x10^6
Mega
x10^9
Giga
x10^12
Tera
Tera
x10^12
Giga
x10^9
Mega
x10^6
Kilo
x10^3
10^-3
milli
10^-6
micro
10^9
nano
10^-12
pico
milli
10^-3
micro
10^-6
nano
10^9
pico
10^-12
What 3 things are needed for an interaction pair
Must be two different objects
Must be the same type of force
Forces must be equal and opposite
Is momentum scalar or vector
Vector