31 terms

# Mechanics

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Speed
Distance travelled in a given time
Displacement
Distance in a given direction
Velocity
Speed in a given direction
Acceleration
Rate of change of velocity with respect to time
Vector
A quantity that has both magnitude and direction in space
Scalar
A quantity that has magnitude in space only and no direction
Force
Mass x Acceleration
Mass
The measure of how difficult it is to accelerate a body
Weight
Mass x Gravity
Momentum
Mass x Velocity
Newton's First Law
States that every body will remain in a state of rest or travelling with a constant velocity unless an unbalanced external force acts on it
Newton's Second Law
States that when an unbalanced force acts on a body the rate of change of the body's momentum is directly proportional to the force and takes in the direction of the force
Newton's Third Law
States that is a body A exerts a force on a body B, then body B exerts an equal but opposite force on body A.
Friction
A force that opposes motion
Principle of Conservation of Momentum
States that in any interaction between two or more bodies the total momentum of the bodies before the interaction is equal to the total momentum after the interaction provided no external forces act on the system of bodies
Density
Mass per unit Volume
Pressure
Force per unit Area
Archimedes' Principle
States that when an object is partially or completely immersed in a fluid it experiences an upthrust equal in magnitude to the weight of the fluid displaced
The Law of Flotation
States that the weight of a floating body is equal to the weight of the fluid it displaces
Boyle's Law
States that at a constant temperature the volume of a fixed mass of gas is inversely proportional to its pressure
Newton's Law of Universal Gravitation
States that any two point masses in the universe attract each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them
Moment
Force X Perpendicular Distance
Laws of Co-planar Forces
When a system is in a state of equilibrium:
1. The vector sum of the forces in any direction is zero
2. The sum of the moments about any point is zero
Couple
Two parallel forces with the same magnitude acting in opposite directions
Torque
Force X Perpendicular Distance
Work
Force X Displacement
Energy
The ability to do work
Principle of Conservation of Energy
States that energy cannot be created or destroyed but can only be converted from one form to another
Kinetic Energy
The energy a body has due to its motion
Potential Energy
The energy a body has due to its position in a force field
Power
Rate at which work is done
or
Rate at which energy is converted from one form to another