2.2 Forces Flashcards
What is force measured in?
Newtons (N)
What forces are always exerted on an object?
Equal and opposite forces
Or
Action and reaction forces
What is the resultant force?
The overall forces acting on an object
When can the resultant force be zero?
If an object is still
Or
An object is moving at constant speed with equal forces acting on it
If the resultant force is more than zero what is the object doing?
It will accelerate in the direction of the greater force
The greater the resultant force…
The greater the acceleration
How does a larger mass affect the force for a particular acceleration?
A larger force is needed
In a car what is total stopping distance?
Thinking distance + breaking distance
In a car what is total stopping time?
Thinking time + breaking time
What is thinking distance affected by?
Alcohol Drugs Tiredness Distractions (talking,music) Experience
What is breaking distance affected by?
Bad weather Ice Bald tyres Road surface Mass of the car Steepness of the road
What affects both thinking and breaking distance?
Speed
What happens when breaks are applied to a vehicle?
Energy by the friction between the brakes and the wheel reduces the kinetic energy of the vehicle
The temperature of the brakes increase
What is terminal velocity?
When an object is freely falling and the two forces (drag and weight) are equal
What happens the a sky diver?
He will initially accelerate as weight is greater than air resistance
Air resistance will increase and equal the downwards force this is terminal velocity
When he releases his parachute air resistance will become greater and he will decelerate
Once the weight equals the air resistance again the sky diver has reached a second terminal velocity
