linear motion Flashcards
linear motion
movement of a body in a straight line with all body parts moving the same distance and direction over the same time
linear motion example
a water skier being pulled at constant speed will travel in linear motion as all parts of their body travel in the same direction over the same distance per unit of time
where is the force applied for linear motion to occur
through the centre of mass
scalar quantities
have magnitude only
scalar quantities examples
- mass
- inertia
- distance
- speed
vector quantities
have magnitude and direction
vector quantities examples
- weight
- acceleration
- deceleration
- displacement
- velocity
- momentum
distance
total length of the path covered from start to finish
displacement
shortest straight line route from start to finish
speed
the rate of chnage of direction (m/s)
speed formula
speed = distance / time taken
velocity
the rate of change in displacement (m/s)
velocity formula
velocity = displacement / time taken
acceleration
the rate in change of velocity (m/s2)
acceleration formula
acceleration = (final velocity - initial velocity) / time taken
deceleration
occurs when the rate of change in velocity is negative or there is a decrease in velocity over time
momentum
measurement of the amount of motion an object has (kgm/s)
momentum formula
momentum = mass x velocity
what does a distance time graph show
speed
what does a displacement time graph show
velocity
what does a velocity time graph show
acceleration
when might a body’s state of motion get quicker?
when diving off the block or pushing off the wall after a turn in swimming
when might a body’s state of motion get slower?
when going into a turn or in the middle of a distance race in swimming
what causes changes in speed and direction?
external unbalenced forces
force
a push or pull that alters the state of motion of a body (N)
force formula
force = mass x acceleration
what are the 2 types of force
internal
external
internal force
a force that originates inside the body e.g. contraction of muscles
external force
a force acting that originates outside of the body e.g. gravity
external force examples
- gravity
- friction
- air resistance
- inertia
gravity
force that pulls objects back down to earth
friction
objects moving against each other in opposition cause friction
air resistance
friction caused by air moving over a surface
inertia
the reluctance of a body to change its state of motion
