Transcript Effective Force & Newton`s Laws

APPLYING AN EFFECTIVE
FORCE & NEWTON’S
LAWS OF MOTION
Week 7
Inertia
A measure of how __________ it is to
change an object’s motion
The greater the inertia, the more difficult it
is to change the __________ of the object
The heavier the object, the greater the
inertia
Inertia
Kicking a ball or kicking a brick…
Which has the greatest inertia?
Momentum
A measure of the amount of motion
possessed by a ___________ body
Velocity: the rate of positional change of
an object
Momentum = mass (kg) x velocity (m/s)
An object can only have momentum if it is
moving
To increase momentum, an object must
either increase its _________ or its
__________
Momentum
Impulse
Application of force over a period of
__________
Changes the velocity of a body or object
Impulse = force x time
Impulse
Impulse & Accuracy
Flattening the arc: The bat/racquet/hand
moves in a straight line at the point of
contact/release
This increases accuracy
Force Reception/Absorption
An object’s force must be received or
absorbed over a distance to slow it and
stop it
Eg: cricket catching – ‘give with the hands’
Newton’s Laws of Motion
1st Law: Inertia
2nd Law: Acceleration
3rd Law: Action & Reaction
First Law of Motion - Inertia
An object whether at rest or in motion will
continue in that state unless it is acted
upon by a force strong enough to change
its state of motion or rest’
First Law of Motion - Inertia
Second Law of Motion –
Acceleration/Momentum
The acceleration of an object is directly
proportional to the amount of force applied
and takes place in the direction in which
the force is applied
Second Law of Motion –
Acceleration/Momentum
Third Law of Motion – Action &
Reaction
For every action there is an equal and
opposite reaction
Third Law of Motion – Action &
Reaction
Conservation of Momentum
The total momentum of two objects before
impact will equal the total momentum after
impact
The momentum of an object is never lost,
but rather _____________ on contact with
other objects
Conservation of Momentum