P2.2 Flashcards
What happens when objects interact
Pairs of forces arise
What is each pair
The forces act in opposite directions
The forces are the same size and type
What is Newton’s third law
For every action there is an equal and opposite reaction.
What are non contact forces
Forces that arise when objects aren’t in contact with each other for example charges, magnets, gravity
what are contact forces
Contact forces are forces that act between two objects that are physically touching each other.
How to draw free body diagrams steps
1) Identify all non-contact pairs
2) Identify all contact pairs
3) Focus on a single object
What are all the forces you can have in a free body diagram
Applied force
Gravity
Tension
Friction
Air resistance
Drag
Normal contact force
How to work out resultant forces
You can work out resultant forces by using Pythagoras’ theorem. Or by using trigonometry.
What is newton’s first law
An object will continue to stay at rest or move with uniform velocity until a force acts upon it.
What is newton’s second law
F = M x A
When an object is moving in a circle at constant speed is it accelerating?
The object is accelerating even though it is moving at constant speed this is because it’s constantly changing direction so the velocity is constantly changing and therefore the acceleration is constantly changing.
What is terminal velocity
Terminal velocity is when the forces are balanced (at equilibrium) this means that the forces acting on a body are equal. For example as a skydiver accelerates down due to weight the force of air resistance eventually equals the weight of the skydiver so they have reached terminal velocity.
What is momentum
Momentum = Mass x Velocity
What is the law of momentum
In any collision the momentum before the collision is equal to the momentum after the collision.
What occurs in an elastic collision
No energy is transferred to other stores and the energy in the kinetic store stays the same.
