Resultant Forces Flashcards
What is force
A push or pulls that acts on an object due to the interaction with another object
Is force scalar or vector
Vector, have both magnitude (size) and direction
What is resultant force
A single force that has the same effect as all of the original forces acting together
(Subtract the smaller force from the larger)
Scalar and vector quantities
Scalar- only has size (magnitude)
Vector- has size and direction
Scalar:
- distance
- time
- speed
- mass
- temperature
- energy
Vector:
- force
- weight
- velocity
- acceleration
- momentum
- displacement (distance in a certain direction)
What are forces measured in
Newtons (N)
Contact forces
- 2 objects physically touching during interaction
- tension
- friction
- air resistance
- normal contact force (2 objects in direct contact applying a force on each other)
Non contact forces
- 2 objects that are physically separate during interaction
- gravitational force
- electrostatic force
- magnetic force
What is mass
- how much matter is in an object
Kilogram (Kg) - mass stays the same everywhere
What is weight
- the force acting on an object due to gravity
Newton (N) - the weight of an object does depend on where it is
Weight = mass x gravitational field strength
What is gravitational field strength
- the measure of the force of gravity in a particular location
- for the Earth, 9.8 g
What is gravitational force measured in
N/kg
What links weight and mass
They are directly proportional to each other
What is centre of mass
- the weight of an object can be considered to act at a single point
- this point is the centre of mass
What makes an object elastic
If it returns to its original shape when the forces deforming it are removed
The increase in length of a stretched material from its original length is called extension
What is the equation
Extension = stretched length - original length
Stretch test required practical
- hang the elastic material from a clamp
- measure it’s original length with a ruler
- hang an empty
- hang a weight from the elastic material and keep increasing it
- the length of the material is measured each time a weight is added
- the total weight added and the total length of the strip are recorded in a table
What is hooke’s law
- the extension of a spring is directly proportional to the force applied, as long as it’s limit of proportionality is not exceeded
Force applied (N) = spring constant (N/m) x extension (metres)
- the stiffer the spring, the greater the spring constant
