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Define scalar quantity
A quantity that only has magnitude
Define vector quantity
A quantity that has both a magnitude and an associated direction
Give an example of a contact force
-friction
-air resistance
-tension
give an example of a non-contact force
-gravitational forces
-electrostatic forces
-magnetic forces
how do you calculate resultant force?
add together the forces
what is the difference between mass and weight?
mass stays the same while weight in dependent on the gravitational field strength
what is the equation linking weight, mass and gravity?
Weight = mass x gravitational field strength
W=mxg
What are the units for weight?
N (newtons)
What are the units for mass?
Kg (kilograms)
What are the units for gravity?
N/kg (newtons per kilogram)
What is equation linking work, force, and distance?
Work done = force x distance the force moved
W=fxd
What are the units for work?
J (joules)
What are the units for force?
N (newtons)
.What are the units for distance?
m (metres)
How do you convert between Joules and Newton-metres?
They are the same
What happens to an elastic object up to the limit of proportionality?
Will continue to expand
What happens to an elastic object after the limit of proportionality?
Will no longer be able to expand
What is the equation linking force, the spring constant, and extension?
force = spring constant x extension
f=ke
What are the units for force?
N (newtons)
What are the units for the spring constant?
N/m (newtons per metre)
What are the units for extension?
m (metres)
What is the equation linking elastic potential energy, the spring constant and extension?
Elastic potential energy =1/2 x spring constant x extension²
Ee=1/2ke²
What are the units for elastic potential energy?
J (joules)
What are the units for the spring constant?
N/m (newtons per metre)
What are the units for extension?
m (metres)
What is a fluid?
liquid or gas
Can a fluid be compressed?
-liquids cannot be compressed
-gases can be compressed
What is the equation linking pressure, force and area?
Pressure= force
area
P=F
A
What are the units for pressure?
Pa (pascal)
What are the units for force?
N (newtons)
What are the units for area?
m² (metres squared)
Examples of scalar quantities
-distance
-speed
Examples of vector quantities
-displacement
-velocity
What is the equation linking distance, velocity and time?
Distance=velocity x time
S=vxt
What are the units for distance?
m (metres)
What are the units for velocity?
m/s (metres per second)
What are the units for time?
s (seconds)
How do you calculate the speed of an object from a distance-time graph?
gradient of the line
When can an object have constant speed but still be accelerating?
if it is changing direction (e.g. in a circle)
How do you calculate the distance travelled from a velocity-time graph?
area under the graph
What is acceleration?
change in velocity over time
How do you calculate acceleration from a velocity-time graph?
gradient of the line
What is the equation linking acceleration, change in velocity and distance?
Acceleration = change in velocity
time
A= Δv
t
What are the units for acceleration?
m/s² (metres per second squared)
What are the units for change in velocity?
m/s (metres per second)
What are the units of time?
s (seconds)
What is the equation linking final velocity, initial velocity, acceleration and time?
Final velocity² x initial velocity² = 2 x acceleration x time
v² -u² = 2 x a x s
If an object is falling due to gravity what acceleration does it have?
9.8 m/s²
Define terminal velocity
velocity of something is travelling at when all forces on it are equal
How is an object moving if the resultant force is zero?
moving at a constant speed or stationary
What is Newton’s first law?
an object will stay stationary or at a constant velocity unless acted on by external forces
Define inertia
Where an object keeps doing what it was going unless acted upon by external forces
What is the equation linking force, mass and acceleration?
Force = mass x acceleration
F= mxa
What are the units for force?
N (newtons)
What are the units for mass?
kg (kilograms)
What are the units for acceleration?
m/s² (metres per second squared)
What is stopping distance?
Thinking and braking distance
Factors that can affect reaction time
-alcohol
-drugs
-tiredness
Factors effecting braking distance
-weight of car
-condition of road/ tyres
Factors that can cause an object to float or sink?
-density
-surface area
What is the equation linking pressure, height, density and gravitational field strength?
Pressure = height x density x gravitational field strength
P = hxpxg
What are the units for pressure?
Pa (pascals)
What are the units for height?
m (metres)
What are the units for density?
kg/m³ (kilograms per metres cubed)
What are the units and value for gravitational field strength?
9.8 N/kg
What is the law of conservation of momentum?
momentum is always conserved
What is the equation linking the momentum, mass and velocity?
Momentum = mass x velocity
P = mxv
What are the units for momentum?
kg m/s (kilograms metres per second)
What are the units for mass?
kg (kilograms)
What are the units for velocity?
m/s (metres per second)
What is the equation linking moment, force and distance?
Moment = force x distance
M= fxd
What are the units for moment?
Nm (newton metres)
What are the units for force?
N (newtons)
What are the units for distance?
m (metres)
What happens to an object if the clockwise and anticlockwise forces are balanced?
it will remain balanced
What happens to an object if the clockwise, anticlockwise forces are unbalanced?
turning effect
What is the equation linking force, mass, change in velocity and change in time?
Force = mass x change in velocity
change in time
F= m x Δv
Δt
