Forces Flashcards
What is a force?
Is a vector quantity-vector quantities have a magnitude and a direction.
Contact forces
Friction
Air resistance
Tention
Normal contact force
Non-contact
Magnetic
Gravity
Static electricity
Equal and opposite forces
When two objects push or pull on each other, they exert equal and opposite forces on one another.
Resultant force is 0
If the resultant force is 0, forces acting on the object are balanced. The object remains stationary or continues to move at the same speed and same direction as before.
Resultant force not 0
The forces on the object are not balanced. The movement of the object depends on the size and direction of the resultant force.
Mass
Number is fixed. It depends on the quantity of matter in it.
Weight
Is the force of gravity on it. It’s measured in Newtons.
Formula: weight=mass*gravitational field strength
Hooke’s law
The extension of an object is directly proportional to the force that is applied to it, as long as it’s limit of proportionality is not exceeded.
Elastic object
If it returns to its original shape when the forces deforming it are removed.
Vector quantities
- force
- velocity
- displacement
- acceleration
- momentoum
Scalar quantities
Physical quantities that only have a magnitude and no direction.
Scalar quantities :
- speed
- distance
- time
Vectors
Represented by arrows. The length of the arrow shows magnitude and the direction of the arrow shows the direction of the quantity.
Gravitational force
Is the force of attraction between masses.
Work done
When a force moves an object trough a distance energy is transferred and work is done on the object.
1 j=
1Nm (Newton meters)
Equilibrium
If all forces acting on an object combine to give a resultant force 0, therefore, the forces are balanced.
Limit of proportionality
There is a maximum force, when the extension is no longer proportional to force.
The energy in the elastic potential energy store (graph)
Is equal to the area under a force-extension graph.
Friction
Is a force between two surfaces, which opposes the motion and may result in heating.
Air resistance
Is a form of friction.
Formula for Extention
F(force) = k (constant) * e (extension)
Forces can change…
the shape of an object or change its state of rest or its motion.
Newton’s Third Law
When two objects push or pull on each other, they exert equal and opposite forces on one another.
Newton’s First Law of motion
If the resultant force on an object is zero, the object:
- remains stationary if it was in equilibrium
- continues to move at the same speed and in the same direction
The resultant force is as a single…
force that has the same effect as all the forces acting on an object.
Newton’s Second Law
If the resultant force is not 0, the object will accelerate in the direction of the resultant force.
Resultant force formula
N = mass (kg) x acceleration (m/s2)
