2- Forces Flashcards
What are action and reaction forces?
When an object applies a force onto another, the other applies a equal yet opposite force upon it (car hitting a barrier)
What are forces measured in
Newtons (N)
What is the resultant force?
The single force that would have the same effect on the object as the multiple forces acting together (all the forces added up)
What does a resultant force which is not zero cause?
An acceleration
What is acceleration?
A change in velocity
What is interesting about acceleration? (Direction)
An object can accelerate (even if at a constant speed) by changing direction
The greater the resultant force the greater the what?
Acceleration
The bigger the mass the bigger the what?
Force needed to accelerate
What is the resultant force if an object is travelling at a constant speed?
Zero
What effects a cars stopping distance?
Braking distance
Thinking distance
How can the thinking distance be increased?
The driver is under the influence of a substance
The driver is tired
How can the breaking distance be increased?
Poorly maintained roads
Bad weather
The conditions of the car
If an object is on earth (not falling) what is it’s downwards force called?
Gravitational field strength
What is the upwards force on a falling object called?
Drag force
How does a falling object reach terminal velocity?
The faster the object falls the greater the drag force (air resistance) becomes. When the drag force becomes equal to gravitational force, terminal velocity is reached
What is terminal velocity
An object falling at a constant velocity
What is an objects extension?
The difference between its original length and it’s new length when stretched
What is an elastic object?
One that regains it’s shape when the force deforming it is removed
On an extension graph, why is the line often straight?
The extension is directly proportional to the force applied (hookies law)
On an extension graph, why does it sometimes bend at the end?
We have exceeded its limit of proportionality and are now applying more force than it’s extension
What is fuel economy?
Reducing the amount of fuel needed for the car to travel
How do you reduce fuel economy?
Reducing the speed of the vehicle and reducing the air resistance
Where are anti skid surfaces used?
Where drivers are likely to stop (before traffic lights)
