Transcript (level 0, 1) Plough Clock

Racing Ahead
By making accurate measurements of speed and acceleration, I
can relate the motion of an object to the forces acting on it and
apply this knowledge to transport safety SCN 4-07b
Today we are going to…
• Relate the motion of transport to the forces
acting upon it.
And we will…
• Be able to provide examples of how
transport is designed to keep us safe.
Lets start off today by
reviewing Newton’s Laws of
Motion…
ZOOOOOM!
And to do this we’ll look at
rockets. Everybody loves
rockets!
Newton’s First Law…
“An object will remain at rest or, continue to move at a
constant speed in a straight line forever, unless it is
acted upon by an unbalanced force.”
The rocket will not move unless it is
acted upon by a force.
If the rocket is moving at a constant
speed, it will continue to move at that
constant speed in the same direction
forever unless it us acted upon by an
unbalanced force…
I’m
going
higher
and
higher
,
foreve
r!
Newton’s Second Law…
“If an object is acted upon by a constant,
unbalanced force then the object moves with a
constant acceleration in the direction of the
constant unbalanced force.”
F=ma
Newton’s Third Law…
“For every action there is an equal but opposite
reaction. OR If A exerts a force on B, B exerts
an equal but opposite force on A”
Thrust
Weight
Newton’s Laws are very
important in car safety…
When there’s a car crash, the people in the car
decelerate rapidly. The forces created in the crash are
very strong, and can cause significant injuries. We
can reduce the likelihood of harm by…
Increasing the time
taken for
deceleration of
occupants to occur.
Crumple Zones, Seat
Belts and Air Bags all
help with this…
How do these feature’s work?
Crumple Zones:
-
Increase the time for a
vehicle to slow down
during impact and
absorb some of the
kinetic energy.
-
This reduces the force
on the people in the car.
How do these feature’s
work?
Air Bags:
-
Increase the time taken for deceleration of a person’s head
to reach zero.
-
A longer time slowing down decreases the deceleration,
preventing it from being short and sharp and reducing the
likelihood of serious injury to the people in the car.
How do these feature’s work?
Seat Belts:
-
-
When a car crashes there are no unbalanced forces acting
upon the person.
This means they continue moving forward
What law of motion is this?
The person exerts a force on the
set belt, the seat belt exerts a
force back on the person
What law of motion is this?
Today we have…
• Reviewed Newton’s Laws of Motion
• Learnt how cars are designed to help reduce
the likelihood of injury in the event of
collisions.