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396 Terms
What is the SI unit of distance
metre m
What is the SI unit of mass
kilogram kg
What is the SI unit of time
second s
What is the SI unit of electric current
ampere A
What is the SI unit of temperature
kelvin K
What does the prefix giga mean
10^9
What does the prefix mega mean
10^6
What does the prefix kilo mean
10^3
What does the prefix centi mean
10^-2
What does the prefix milli mean
10^-3
What does the prefix micro mean
10^-6
What does the prefix nano mean
10^-9
How do you convert hours into seconds
Multiply by 3600
How do you convert kilometres into metres
Multiply by 1000
How do you convert centimetres into metres
Divide by 100
How do you convert millimetres into metres
Divide by 1000
How do you convert grams into kilograms
Divide by 1000
What is standard form
A number written as A x 10^n where A is at least 1 and less than 10
What is a scalar quantity
A quantity with magnitude only
What is a vector quantity
A quantity with magnitude and direction
Give examples of scalar quantities
Distance speed mass time energy and temperature
Give examples of vector quantities
Displacement velocity acceleration force and momentum
What is the difference between distance and displacement
Distance is the amount of distance traveled (m)
Displacement is amount of distance travelled from origin
speed équation
Distance / time
What is the equation for distance
speed x time
What is the equation for time
distance / speed
What is velocity
Speed in a stated direction
What does the gradient of a distance-time graph represent
Speed
What does a horizontal line on a distance-time graph represent
The object is stationary
What does a steeper gradient on a distance-time graph represent
A greater speed
What does a straight sloping line on a distance-time graph represent
Constant speed
What does a curved line on a distance-time graph represent
Changing speed
How do you calculate speed from a distance-time graph
Calculate the gradient using change in distance divided by change in time
What is acceleration
The rate of change of velocity
What is the equation for acceleration
acceleration = change in velocity / time taken
What is the unit of acceleration
m/s^2
How do you calculate change in velocity
Final velocity minus initial velocity
What does the gradient of a velocity-time graph represent
Acceleration
What does the area under a velocity-time graph represent
Displacement
How do you calculate distance from a velocity-time graph when velocity is positive
Calculate the area under the graph
What does a horizontal line on a velocity-time graph represent
Constant velocity
What does a straight sloping line on a velocity-time graph represent
Constant acceleration
What does a curved line on a velocity-time graph represent
Changing acceleration
What equation links final velocity initial velocity acceleration and displacement
v^2 - u^2 = 2ax
In v^2 - u^2 = 2ax what does u represent
Initial velocity in m/s
In v^2 - u^2 = 2ax what does v represent
Final velocity in m/s
In v^2 - u^2 = 2ax what does a represent
Acceleration in m/s^2
In v^2 - u^2 = 2ax what does x represent
Displacement in metres
How can you measure the speed of a trolley using light gates
Measure the time taken for a card of known length to pass through a light gate then calculate speed
How can you calculate average speed
Measure total distance travelled and divide by total time taken
What is the approximate speed of sound in air
330 m/s
What is the approximate speed of light in a vacuum
3 x 10^8 m/s
What is gravitational field strength near Earth's surface approximately
10 N/kg
What happens to a freely falling object near Earth when air resistance is negligible
It accelerates at approximately 10 m/s^2
What is Newton's first law
An object remains at rest or moves at constant velocity unless acted on by a resultant force
What is the resultant force
The overall force acting on an object after all forces are combined
What happens when the resultant force on an object is zero
It remains stationary or continues at constant velocity
What is Newton's second law
resultant force = mass x acceleration
What is the unit of force
newton N
What happens to acceleration if resultant force increases while mass stays constant
Acceleration increases in proportion to resultant force
What happens to acceleration if mass increases while resultant force stays constant
Acceleration decreases
What is Newton's third law
When two objects interact they exert equal and opposite forces on each other
Why do Newton's third law forces not cancel each other out
They act on different objects
What is weight
The force acting on an object due to gravity
What is the equation for weight
W = mg
What do W m and g represent in W = mg
Weight in N; mass in kg; gravitational field strength in N/kg
What is the difference between mass and weight
Mass is measured in kg and does not change with location; weight is a force measured in N and depends on gravitational field strength
How can weight be measured
Using a calibrated newton meter or force meter
What is the aim of the force mass and acceleration core practical
Investigate how acceleration depends on resultant force and mass
How can acceleration be measured in the force mass and acceleration practical
Use light gates and a card of known length or a motion sensor
What should be kept constant when investigating force and acceleration
The total mass of the trolley system
What should be kept constant when investigating mass and acceleration
The resultant force acting on the system
Why should friction be reduced in the force mass and acceleration practical
To make the measured resultant force closer to the applied force
What is circular motion
Motion along a circular path
Why does velocity change during circular motion
Its direction is constantly changing
What force keeps an object moving in a circle
A resultant force directed towards the centre
What is centripetal force
The resultant force directed towards the centre of a circular path
What is inertial mass
A measure of how difficult it is to change an object's velocity
How can inertial mass be calculated
mass = resultant force / acceleration
What is momentum
The product of mass and velocity
What is the equation for momentum
p = mv
What is the unit of momentum
kg m/s
What is the equation linking force change in momentum and time
force = change in momentum / time taken
How do you calculate change in momentum
Final momentum minus initial momentum
What happens to average force if the time taken for a momentum change increases
The average force decreases
Why do airbags reduce injury risk
They increase the time taken for momentum to change and reduce the average force
What is reaction time
The time between detecting a stimulus and responding
What is thinking distance
The distance travelled during the driver's reaction time
What is braking distance
The distance travelled after the brakes are applied until the vehicle stops
What is stopping distance
Thinking distance plus braking distance
What factors affect thinking distance
Driver reaction time and vehicle speed
What factors affect braking distance
Vehicle speed road and weather conditions tyre condition brake condition and vehicle mass
How does tiredness affect stopping distance
It can increase reaction time and therefore increase thinking distance
How can alcohol and drugs affect stopping distance
They can increase reaction time and therefore increase thinking distance
Why does greater speed increase thinking distance
The vehicle travels further during the same reaction time
Why does greater speed increase braking distance
The vehicle has more kinetic energy that must be transferred
Why does braking distance increase rapidly as speed increases
Kinetic energy is proportional to speed squared
Why can heavy braking be dangerous
Large decelerations produce large forces on passengers
What is deceleration
Acceleration opposite to the direction of velocity
How does kinetic energy change when speed doubles
It becomes four times greater