GCSE AQA Physics P2 Forces flashcards

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