State Newton’s 3rd law of motion
- “When you push something it pushes you back just as hard, but in the opposite direction”
- “for every action there is an equal opposite force”
State the formula of momentum
p=mv
State the formula linking force, change in momentum, and time
F=(mv-mu)/t
2 things drag force depends on
- shape
- speed
Define drag coefficient
How easily an object can move through air
Define terminal velocity
steady speed achieved by an object freely falling through a gas or liquid.
Define momentum
A measure of how hard it is to stop a moving object
The law of momentum in collisions
Momentum before collision=momentum after collision
*the momentum has just been conserved, one object gains the momentum the other object lost
How do crumple zones improve survival rate?
In a crash, the victim dies because of the exceeding force on them. The crumple zones decrease time, increase deceleration hence in the formula; F=ma, the deceleration decreases the force overall, hence improving survival rate.
Newtons 3rd law and momentum displayed on a rocket taking off
- Every force has an opposite reaction; rockets fuel falling down, rocket goes up
- momentum; velocity of feul being exhuased downwards meaning the rockets velocity increases as it goes upwards, p=mv, velocity increasing meaning momentum increases.
Formula for speed
Speed=distance/time
Formula for velocity
velocity=displacement/time
Formula of acceleration
a=(v-u)/t
stopping distance=…
thinking distance+breaking distance
Define thinking distance
The driver will have a reaction time to the object on the road, this reaction time between him seeing the object and pressing the breaks is the
Factors affecting thinking distance
- age
- tiredness
- loudness
- alchohol
- speed of car
Factors affecting stopping distance
- weather
- speed of car
define stopping distance
distance crossed between driver pressing breaks and the car stopping
in a velocity-time graph, where can i find the distance?
under the line
Outline an experiment to measure the speed of cars
- using a click measure, measure 50 m distance between you and your partner
- Start a timer when your friend signals a car has passed the first point
- Stop the timer once car passes
- Use s=d/t to find the speed
*this experiment is heavily based on reaction time; hence it may not be accurate.
What do I multiply m/s with to convert it to km/h
x3.6
In a distance-time graph, what is the gradient?
speed
WHta is the gradient of a velocity-time graph representing?
acceleration
If both forces sum up to zero, what will happen?
Nothing
