P2.2 +2.3 Newtons Laws and springs Flashcards
What is Newtons first law?
An object at rest remains at rest, and an object in motion remains in motion at constant speed unless acted on by an unbalanced force
What is Newtons second law?
F = MA
What is Newtons third law?
Every reaction has an equal and opposite reaction
What are the three non contact forces?
Electrostatic
Magnetism
Gravity
What is the normal contact force?
The opposite force, eg - elephant is on the ground , the normal contact forces are the force of the elephant on the ground and the force of the ground on the elephant
Name 4 contact forces?
Upthrust
Drag
Tension
Friction
What is the resultant force?
Overall force on object
What is terminal velocity?
When your motion no longer changes
What is the law of conservation of momentum?
In any collision momentum is conserved, so the momentum before is equal to the momentum after
What happens when objects collide with elastic collision?
No energy is transferred between stores, the energy in the kinetic store stays the same
What is inelastic collision?
Energy is transferred to other stores, there is a loss of kinetic energy
What is work?
Using forces to transfer energy between stores
What is power?
Rate at which energy is transferred
What happens when plastic material is stretched?
They do not return to their original shape, deformed
What happens when elastic material is stretched?
They return to their original shape when force is removed
What does the graph of force against extension for a spring show?
Straight line up to a certain point which then go into the limit of proportionality
What is the elastic limit?
Below the elastic limit, if you remove the force, spring returns to normal length. Above limit, doesn’t return to normal length
What is Hookes Law
If you double the force on a spring, the extension doubles. The extension of a spring is proportional to the force until limit of proportionality is reached
what is the spring constant?
measure of the stiffness of the spring
What does the graph for an elastic band show?
A non linear relationship
Explain the graph for blowing up a balloon?
At first it is difficult, the rubber is stiff however once you start it requires less force to produce an extension
What is weight and mass measured in? two different things
Mass - Kg
Weight - N
What is gravitational potential energy?
When you lift an object in a gravitation field, you transfer energy to a gravity store
