Runner A finishes a race in less time than runner B. Who is faster?

Runner A

What two measurements are needed to calculate speed?

distance and time

What is the SI unit for speed?

m/s

What does acceleration mean?

speeding up or slowing down

What is a force?

push or pull

How do we represent forces on diagrams?

arrows, with length depending on size of force

What does mass mean?

amount of substance

What is the unit for mass?

kilogram

What does a vector have that a scalar does not?

direction

Name a scalar and a vector measured in metres.

distance, displacement

Name a scalar and a vector measured in metres/second.

speed, velocity

Name a vector with units of newtons.

force or weight

Is mass a vector or scalar?

scalar

Is energy a vector or scalar?

scalar

What is acceleration?

a change in velocity

Why is acceleration a vector?

it is measuring a change in another vector

What is the difference between speed and velocity?

velocity has a direction/is a vector

What is the equation for calculating speed?

speed = distance / time

What is the SI unit for speed?

metres per second

What is the equation for average speed?

total distance / time for whole journey

What is the equation for calculating distance?

distance = speed x time

How is a constant speed shown on a distance/time graph?

straight, sloping line

What does a horizontal line on a distance/time graph show?

stationary object

What is the speed of sound in air?

approximately 330m/s

How is a stationary object shown on a distance/time graph?

horizontal line

How can you tell which part of a journey shown on a distance/time graph has the highest speed?

steepest line

How can you calculate velocity from a distance/time graph?

gradient of line

What does acceleration mean?

change in velocity in time

What are the units for acceleration?

metres per second squared

In the acceleration equation, what does u stand for?

initial velocity

In the acceleration equation, what does v stand for?

final velocity

What is the equation for calculating acceleration?

change in velocity/time

What is the acceleration due to gravity?

10m/s2 to 1 sig. fig or 9.8m/s2 to 2 sig. fig.

What is the force that pulls us towards the Earth?

gravity

What is ‘drag’ another name for?

air resistance or water resistance

What are balanced forces?

forces of the same size in opposite directions

What do we call the forwards force produced by an aeroplane’s engine or propeller?

thrust

What word describes both the speed and direction of movement of an object?

velocity

What is the name for a single force on an object with the same effect as all the forces combined?

resultant

How do we describe the forces on an object when the force in one direction is bigger than the force in the other?

unbalanced

Two forces on an object are in the same direction. How do we calculate the resultant force?

add

Two forces on an object are in opposite directions. How do we calculate the resultant force?

find the difference between them

What does the length of a force arrow on a diagram represent?

size of force

An aeroplane has thrust of 2000N and drag of 1800N. What is the resultant?

200N forwards

Air resistance on a cyclist is 20N and friction is 5N. What is the total force trying to slow the cyclist down?

25N backwards

Name a vector quantity that changes as a car drives at constant speed around a roundabout.

velocity

What are unbalanced forces?

forces of different sizes in opposite directions

What is the direction of the resultant force on a car that is speeding up?

forwards

What is the direction of the resultant force on a bicycle that is slowing down?

backwards

How does a sideways resultant force affect the velocity of a moving object?

changes its direction

How can the pilot of an aeroplane make the plane gain speed upwards?

increase the lift/upwards force

How do balanced forces affect the velocity of a moving car?

The car continues with the same velocity.

You pedal harder on a bicycle. What happens?

you accelerate/get faster

What is the name of the force that makes objects move in a circular path?

centripetal

What provides the centripetal force for a car going around a roundabout?

friction

What are the forces on a moon orbiting around a planet?

gravity acting towards the planet

In which direction does centripetal force act?

towards the centre of the circle .

Why is the force of gravity greater on a lorry than on a car?

larger mass

Why is the resultant force accelerating a car usually less than the force provided by its engine?

air resistance and/or friction

Name one force that usually has to be taken into account when working out the resultant force on a moving object

drag or friction

When will a resultant force act to slow a car down?

when backwards forces are greater than forwards ones

How can friction act to make a car speed up?

between tyres and road

How can friction act to make a car slow down?

in brakes

What is the formula linking force, mass and acceleration?

F = m x a

An object is moving at a constant velocity. What can you say about the forces on it?

balanced

What is the equation relating to constant velocity?

speed = distance / time

What type of force is used to slow down a moving vehicle?

friction

Where is this force applied?

brakes, tyres

Why is a wet road more slippery than a dry one?

water acts as lubricant

An object has a negative acceleration. What does this mean?

it is slowing down

What effect does drinking alcohol have on human reaction times?

slows them down/makes them longer

How will being tired affect reaction time?

make it longer

What does braking distance mean?

the distance a car travels while slowing down

What does thinking distance mean?

the distance a car travels while the driver is reacting to a danger and deciding to apply the brakes

How does speed affect the thinking distance?

higher speed, longer thinking distance/thinking distance directly proportional to speed

How does speed affect the braking distance?

higher speed, longer braking distance/braking distance proportional to speed squared

How does the force needed for an acceleration depend on the size of the acceleration?

larger acceleration, larger force needed

What does deceleration mean?

slowing down/a negative acceleration

What factors affect the momentum of a moving object?

mass, velocity

How does the mass affect momentum?

higher mass, higher momentum

How does the velocity affect momentum?

higher velocity, higher momentum

What does momentum is conserved mean?

total momentum is the same before and after a collision