P2- Forces Flashcards
When two objects interact…
They always exert equal and opposite forces on each other.
What is resultant force?
The resultant force is a single force that has the same effect as all the forces acting on an object.
When the resultant force is at zero:
- If the object is at rest, it will stay at rest.
- If the object is moving, it will carry on moving in the same direction and speed.
What is the resultant force of a 5N force and a 8N force acting in the same direction?
13N in the same direction.
How can we calculate resultant force?
F= m x a
F= force in N.
m= mass in kg.
a= acceleration in m/s2
What happens to the acceleration of an object if the mass increases?
Acceleration decreases because a bigger force is needed to give a particular acceleration.
What forces would oppose the driving force of a car?
Friction and air resistance.
What is stopping distance?
Thinking distance + braking distance.
How can thinking distance be increased?
If the driver is:
- Tired.
- Under influence of drugs.
- Under influence of alcohol.
What are forces measured in?
Newtons, N.
How can braking distance be increased?
- Poorly maintained roads or bad weather conditions.
- Condition of car➡️e.g: worn tyres or worn brakes.
What is mass and what is it measured in?
Mass is the amount of matter in an object.
An object has the same mass everywhere i.e: Earth or outer space. Mass is measured in kilo grams.
What is weight and what is it measured in?
Weight is the force of gravity attracting the mass towards the centre of the Earth. Weight is measured in newtons (N).
What is the equation to calculate the weight?
Weight (N)= Mass (kg) x gravitational field strength (N/kg).
What is meant if a falling object has reached terminal velocity?
The falling object has reached a steady speed where drag/(air) resistance= weight.
