motion

motion

occurs when an object changes changes position reative to a referance point

scarlars

have size only, no direction

scalars examples

Length, Time, Speed

scalars size represented

by number e.g speed (55m/s)

vectors

have size and direction

vector examples

Displacement, Velocity, Force, Momentum

vectors size represented

by number w/ a unit e.g velocity (33m/s, west)

vectors direction represented

N/S/E/W or an arrow

how they relate to motion

measurements such as force momentum, speed and time define how much motion occurs

distance

• symbol: d

• how far apart two objects are

• units: m and km

• always positive number

distance example

You swim an 100 meter lap in a race. You then swim another 100 meter lap, back to where you started, the distance you’ve travelled is 200 meters.

displacement

• symbol: s

• a straight line from start point to end point

• can be positive or negative

• units: m and km

• vector: include direction

displacement example

You swim an 100 meter lap in a race. You then swim another 100 meter lap, back to where you started, the displacement is zero.

speed

• symbol V

• rate at which an object moves over a distance

• scalar

• m/s or km/m

speed formula: as well as distance + time

speed form: s:d/t

d= distance

s: speed

t: time

if you have a distance in m and a time in s then speed with be

m/s

if you have a distance in km and a time in hr than speed will be

km/h

average speed

average speed of an object throughout journey

average speed calculated for speed

using V= d/t

( does not count for changing speed, starting or stopping)

instantaneous speed

speed at particular instant

e.g speed camera

triangle formula ofIDK

d= v x t

d= distance

v= velocity/speed

t= time

acceleration definition

rate of change in velocity over time

• can be both positive or negative

why is acceleration a vector

has both a direction and magnitude

acceleration units

units: m/s/s, m/s2, ms-2 OR km/h/s

acceleration formula

a= v-u / t

• a= acceleration

• v= velocity

• u= initial velocity

• t= time

graphing acceleration- quick + slow

graphing acceleration- deceleration

graphing acceleration- no acceleration

acceleration due to gravity (9.8m/s²)

every second an object is in free fall, gravity will cause the velocity of the object to increase 9.8 m/s. (each second +9.8)

The maximum speed it can reach will be affected by

air resistance

How much force a human can tolerate depends on:

• how big the force is

• how long it lasts

• the direction in which it acts

• the part of the body that is affected

(vertical drop dangerous as blood flow to the brain can be disrupted)

distance time graphs

steeper slope= faster

less steep= slower

flat line= stationary

finding gradient will find speed

speed time graphs (velocity)

upwards: speed increasing

downwards: speed decreasing

flatline: constant speed

displacement time graphs

slope up: moving away from start

slope down: moving back to start point

flatline: stationary

force

a push or pull motion that alters an object

e.g speeding it up

• symbol: F

• unit: N (newtons )

• vector

newtons first law

an object at rest will remain at rest unless it is acted upon by a force

• also applies to moving objects

• will keep going at same speed and same direction until a force acts

first law- inertia

an objects tendency to resist any chance in motion e.g on a moving train

newtons second law

an object will accelerate in the direction of an unbalanced force acting upon it

• the acceleration will depend on mass of object + size of force

F= m x a

f=m x a

F= force in newtons

m= mass in kg

a= acceleration m/s2

grams → kg → t

1000

m/s → km/h

3.6

newtons third law:

for every force there is an equal and opposite reaction force

example of force- same direction

• add the numbers together

example of force- opposite direction

• subtract the numbers from each other

  • if arrow same direction: add

  • if arrow opposite: subtract

balanced force

equal and opposite forces acting on an object

• will not result in any change of movement

unbalanced force

unequal forces acting on an object

• will result in change of speed, change of direction, change of shape, stopping or starting to move

finding distance using

Pythagoras a2+b2=c2

motion graph example

net force

the total force acting on an object, calculated as the vector sum of all individual forces