Forces & Motion Flashcards
What can forces change?
Change a shape of something, it’s speed or the direction it moves in
What is a contact force?
A force where there needs to be contact between objects before the force can have an affect
Example of contact forces
Air resistance, water resistance, upthrust and friction
What is a non contact force?
A force that can affect something from a distance
Example of non contact forces
Gravity, static electricity and magnetism
Where does air resistance react?
Against the force of movement
What is extension?
The amount by which a spring or other stretchy material has stretched
How do you calculate stretched length?
Stretched length subtract (-) original length
What is elastic?
An elastic material changes shape when there is a force on it but returns to its original shape once the force is removed
What is limit of proportionality?
the extension of a spring is proportional to the force on it up to a certain point
What is hookes law?
The law that says the extension of a spring is proportional to the force on it
What are plastic materials?
Materials that do not return to their original shape when a force is removed
What material is good to reduce friction?
Rubber
What can friction do?
Slow things down or make them stay still
What is reducing friction called?
Lubricants or lubrication
Examples of lubricants?
Oil or grease
How can air resistance and water resistance be reduced?
By having smooth surfaces and smooth shapes
What is pressure?
The amount of force pushing on a certain area
What is the formula to calculate pressure?
Pressure = force/area
If forces are unbalanced on a moving object what will happen?
It will change it’s speed
What do all stationary objects have on them?
Balanced forces
List different forces
Friction, reaction, thrust, gravity, air resistance, water resistance, magnetic force, upthrust, tension, weight
Name stores of energy?
Kinetic, nuclear, chemical, elastic potential energy, gravitational potential energy, thermal
Name energy transfers?
Heat, sound, light, force, electricity
What is the law of conservation energy
energy cannot be created or destroyed it can only be transferred
What are the units of force?
Newtons
What are the units of distance?
Metres
What is the centre of mass?
the centre of mass is the point at which the object will balance. The force of gravity acts through the centre of mass
What is another name for turning effect?
Moment
What is the formula to find out moment?
Moment = force x distance from pivot
What is the equation for work done?
Work done = force x distance in the same direction as force
