Basic Mechanics Flashcards
Define Mass and what is its unit of measurement?
Mass is defined as the measure of how much matter is in an object it’s SI Unit (Kg)
Define weight and what is its unit of measurement?
Weight is the force exerted on an object of mass by gravity (9.81) and is measured in newtons
Define acceleration and what is the formula for it using final and initial velocity V and U
Acceleration is the change in velocity with time Acceleration = (final velocity (V) - Initial Velocity (U)) / time
Define work done and give an example of the formula for work done also referred to as energy
Work done is the measurement of force across a distance / Energy is the capacity for doing work Work done = Energy Work done = Force x Distance Measured in Joules
Define Power and the give a formula for KWH
Power is defined as the rate of doing work, the unit of power is the watt. Since a watt is a small unit the kilowatt is used 1 KW = 1000 Watts 1 Hour = 60 x 60 Seconds 3600 Seconds 1 KWH = 1000 x 3600 = 3, 600, 000 Joules
Give a formula for average power
Average power= Amount of work done / Time taken to do it
Define efficiency and give a formula for working output power and input power
Efficiency can be defined as the ratio of output power to input power. Output = Input - Losses Input = Output + Losses
Define a Class 1 Lever
A class 1 lever has the load and effort on opposite sides of the fulcrum - effort is applied on one side of the fulcrum and the resistance on the other side Example:
Define a class 2 Lever
Resistance has the load and effort on the same side - The effort is applied on one side of the resistance and the fulcrum is located on the other side. For example a wheel barrow, a nutcracker or a bottle opener and pliers.
Define a class 3 lever
Effort and load are on the same side of the fulcrum but the effort is closer to the fulcrum and than the load - The resistance is applied on one side of the effort & fulcrum is located on the other side, for example a pair of tweezers:
Give a forumla for calculating effort when it comes to levers
Effort = Load x Load to fulcrum distance /
Effort to fulcrum distance
What are Gears used for ?
Gears are used for transmitting power from on part of a machine to another
Asside from transfering power from one part of a machine to another give anther 3 examples as to what gears can be used for?
Increase/decrease speed
increase/decrease power
change direction
What type of cog would you use to change direction when using gears?
An idler cog
What is the name of the two main cogs in mechanical gears?
driving cog
driven cog
