Forces Flashcards
What is a scalar quantity?
One that has magnitude (size) but not direction
What is a vector quantity?
One that has magnitude (size) and direction
What are some examples of a scalar quantity?
Distance
Energy
Speed
What are some examples of a vector quantity?
Displacement
Velocity
Acceleration
What is normal contact force?
The support force exerted upon an object that is in contact with another stable object; the normal contact force is always perpendicular to the surface
What are some examples of non-contact forces?
Electrostatic, magnetic and gravitational
What is the centre of mass?
The point in an object from which its weight acts
If the forces on an object are balanced, we say that the object is in equilibrium
What is the equation for finding work done using displacement?
W = F x s
Who discovered a law for elastic materials?
Robert Hooke
What does Hooke’s law state?
The extension of an elastic object is directly proportional to the force applied, provided the limit of proportionality is not exceeded
What is the equation created by Hooke’s law?
Force = spring constant x extension
What do levers do?
They are used to produce a turning effect with ease in order to make tasks easier e.g. opening a door
What is a moment?
A measure of a forces tendency to cause a body to rotate
What can cause a moment to increase?
The size of the applied force
The perpendicular distance from a pivot the force is applied
What is the equation to calculate a moment?
Moment = force x distance
What are pulleys and gears used for?
Increasing or decreasing a rotational force (turning effect) in machines