AQA GCSE Physics - FORCES (FT)

______ quantities have magnitude only

Scalar

______ quantities have magnitude and an associated direction

Vector

A vector quantity may be represented by an _____

arrow

The length of the vector arrow represents the _________ of the vector quantity

magnitude (size)

The direction of a vector arrow represents the _________ of the vector quantity

direction

A force is a ____ or ____ that acts on an object

push or pull

_______ Forces require objects to be physically touching

Contact

Objects can be physically separated and experience a __________ force

non-contact

Examples of contact forces include ________, air resistance, _______ and normal force

friction, air resistance, tension and normal force

Examples of non-contact forces are gravitational force, _____________ force and magnetic force

gravitational pull, electrostatic force and magnetic force

Force is a ______ quantity

vector

______ is the force acting on an object due to gravity

Weight

The force of gravity close to the _____ is due to the gravitational field around the _____

Earth

The ______ of an object depends on the gravitational field strength at the point where the object is

weight

The equation relating weight and mass is...

Weight = mass x gravity strength (W=mg)

The unit of weight, W

Newtons, N

The unit of mass, m

kilograms, kg

The unit of gravitational field strength, g

Newtons per kilogram, N/kg

The weight of an object may be considered to act at a single point referred to as the object's ______ __ ____

centre of mass

The weight of an object and the mass of an object are ________ ____________

directly proportional

Weight is measured using a ___________

newtonmeter

A number of forces acting on an object may be replaced by a single force that has the same effect as all the forces acting together. This single force is called the _________ _____

resultant force

When a force causes an object to move through a distance ____ is done on the object

work

A force does work on an object when the force causes a ____________ of the object

displacement

The equation for Work Done is...

Weight = Force x distance (W=Fs)

The unit of work done, W

Joules, J

The unit of force, F

Newtons, N

The unit of distance, s

metres, m

One _____ of work is done when a force of one newton causes a displacement of one metre

Joule

1 joule = 1 ______-_____

Newton-metre (1J = 1Nm)

Work done against the frictional forces acting on an object causes a rise in the ___________ of the object

temperature

To change the shape of an object (by stretching, bending or compressing), ____ ____ ___ force has to be applied

more than one

After _______ deformation of an object, it will return to it's original shape

elastic

After _______ deformation of an object, it will NOT return to it's original shape

inelastic

Hooke's Law: The extension (or compression) of an elastic object, such as a spring, is ________ ____________ to the force applied

directly proportional

Hooke's Law only applies to an elastic object provided that the _____ __ _______________ is not exceeded

limit of proportionality

The equation relating force applied to- and extension of an elastic object is...

Force = spring constant x extension (F=ke)

The unit of spring constant, k

Newtons per metre, N/m

The unit of extension (or compression), e

metres, m

A force that stretches (or compresses) a spring does work and _______ _________ energy is stored in the spring

elastic potential

Provided the spring is not inelastically deformed, the work done on the spring and the elastic potential energy stored are _____

equal

The equation relating elastic potential energy stored in- and extension of an elastic object is...

________ is how far an object moves

Distance

Distance is a ______ quantity and so does not involve direction

scalar

Displacement includes both the distance an object moves, in a straight line from A to B, and the _________ of that straight line

direction

Displacement is a ______ quantity

vector

Speed is a scalar quantity and so does not involve _________

direction

The speed of a moving object is ______ constant

rarely

When people walk, run or drive their speed is constantly ________

changing

The speed at which a person can walk, run or cycle depends on many factors including:

age, terrain, fitness and distance travelled

Typical value of walking speed:

̴ 1.5 m/s

Typical value of running speed:

̴ 3 m/s

Typical value of cycling speed:

̴ 6 m/s

It is not only moving objects that have varying speed. The speed of _____ and the speed of the ____ also vary

sound and wind

A typical value for the speed of sound in air is ___m/s

330m/s

The equation relating speed, distance and time is:

distance = speed x time (s=vt)

Unit of speed, v

metres per second, m/s

Unit of time, t

seconds, s

The ________ of an object is its speed in a given direction

velocity

Velocity is a ______ quantity

vector

If an object moves along a straight line, the distance travelled can be represented by a ________-time graph

distance

The _____ of an object can be calculated from the gradient of its distance-time graph

speed

The gradient of a linen a graph can be calculated using:

Gradient = Change in y-axis / change in x-axis

The average acceleration of an object can be calculated using the equation:

acceleration= change in velocity / time taken

Unit of acceleration, a

metres per second squared

Unit of change in velocity, Δv

metres per second, m/s

An object that slows down is ____________

decelerating

The ____________ of an object can be calculated from the gradient of a velocity-time graph

acceleration

The equation relating constant acceleration, distance and velocity is:

Unit of final velocity, v

metres per second, m/s

Unit of initial velocity, u

metres per second, m/s

Near the Earth's surface any object falling freely under gravity has an acceleration of about ___

An object falling through a fluid initially ___________ due to the force of gravity

accelerates

Eventually the resultant force on a falling object will be zero, and it will move at its ________ ________

terminal velocity

Newton's First Law: If the resultant force acting on an object is zero and the object is stationary, the object _______ __________

remains stationary

An object that travels at in one direction at constant speed has an unchanging ________

An object that travels at in one direction at constant speed has an unchanging velocity

Newton's First Law: If the resultant force acting on an object is zero and the object is moving, the object continues to move at ________ ________

constant velocity

When a vehicle travels at a steady speed the resistive forces balance the _______ force

driving

The velocity (speed and/or direction) of an object will ONLY change if a _________ force is acting on it

resultant

Newton's Second Law: The acceleration of an object is ____________ to the resultant force acting on the object

proportional

Newton's Second Law: The acceleration of an object is inversely proportional to the ____ of the object

mass

Newton's Second Law: The greater the resultant force on an object, the _______ the acceleration of the object

greater

Newton's Second Law: The greater the mass of an object, the _______ the acceleration of the object

smaller

symbol for proportionality

The equation for Newton's Second Law:

Resultant Force = mass x acceleration (F=ma)

Symbol that indicates an approximate value is

Newton's Third Law: Whenever two objects interact, the forces they exert on each other are _____ and ________

equal and opposite

The stopping distance of a vehicle is the sum of the ________ distance and the _______ distance

thinking and braking

Thinking distance is the distance travelled during the driver's ________ ____

reaction time

Braking distance is the distance travelled while _______

braking

For a given braking force the greater the _____ of the vehicle, the greater the stopping distance

speed

Reaction times vary from person to person. Typical values range from ___s to ___s

0.2s to 0.9s

A driver's reaction time can be affected by _________, _____ and _______

tiredness, drugs and alcohol

____________ may also affect a driver's ability to react

Distractions

The _______ distance of a vehicle can be affected by adverse road and weather conditions and poor condition of the vehicle

braking

Adverse road conditions include ___ or ___ conditions

wet or icy ONLY

Poor condition of the vehicle is limited to the vehicle's _____ or _____

brakes or tyres

When a force is applied to the brakes of a vehicle, work is done by the ________ force between the brakes and the wheel

friction

When a force is applied to the brakes of a vehicle, work done by the friction force between the brakes and the wheel reduces the ______ energy of the vehicle

kinetic

When a force is applied to the brakes of a vehicle, work done by the friction force between the brakes and the wheel reduces the kinetic energy of the vehicle and the ___________ of the brakes increases

temperature