Forces Flashcards
What are scalar quantities?
Only have magnitude
What are vector quantities?
Have magnitude and direction
What is a force?
A push or pull on an object caused by an interaction with another object. Forces are vector quantities
What are contact forces?
Occur when two objects are touching each other
What are non-contact forces?
Act at a distance - gravitational, magnetic, electrostatic
What happens when an object exerts a force on another object?
It experiences an equal and opposite force
What is a resultant force?
If two or more forces act along the same line
Difference of in opposite directions
Sum if in same direction
What happens when the resultant force is 0?
The forces are said to be balanced
What is a scale drawing?
Used to find the resultant force when the forces are not acting along the same line
Form a triangle
What is a free body diagram?
Shows all the forces acting on a single object
Dota represents object
Arrow direction and size represent direction and magnitude of force
How do you calculate weight?
Mass x gravitational field strength
What is deformation?
Change in the shape of an object caused by stretching, compressing, twisting or bending
What has to happen to cause deformation?
Two or more forces have to act
What is elastic deformation?
The object can go back to its original shape and size when the forces are removed
What is inelastic deformation?
The object does not go back to its original shape or size when the forces are removed
What is the relationship between force and extension?
The extension of an object is directly proportional to the force, as long as the limit of proportionality is not exceeded
Gradient = spring constant
What does ke =?
F
What is elastic potential energy?
A force that stretches or compresses an object does work on it, causing energy to be transferred to the elastic potential store
How is elastic potential energy measured?
Ee = 0.5xkxe^2
What are resolving forces?
A single force can always be split into two components at right angles to each other
What is a moment?
A force or system of forces can cause an object to rotate. The turning effect of the force is called the moment of the force.
M = Fd
The sum of the clockwise moments equals the sum of the anti clockwise moments when an object is balanced
What are levers and gears?
Used to increase the moment of a force, making it easier to lift or rotate an object
If a small gear drives a large gear the moment is increased but the large gear moves slower
A lever allows a large movement of force to be produced by allowing force to be applied further from the pivot
What is normal contact force?
Opposite to weight
How do you measure weight?
A calibrated spring balance
