USE OF MACHINES A machine is a device or tool which allows a force (or effort) applied at one point to overcome a resisting force (or load) at another point. - a device that makes work easier, faster and more convenient. comprises a stationary and moving parts combined together to generate mechanical energy Uses of Machines as a force multiplier when load > effort as a speed multiplier in gears to reduce or increase speed as a displacement multiplier eg in a bicycle (wheel axle) na little movement of the pedal results to a large movement of the wheels. transforms mechanical energy to electrical to change the direction of a force eg in pulley systems downward force is used to move a load upward. 6. if a machine is frictionless, efficiency is equal to 100% and MA = V.R.
Classes Of Machines In Terms Of Performance Generates mechanical energy Utilizes mechanical energy Transforms mechanical energy Need For Use Of Machines In Doing Work Machines are used in all homes, schools, in offices, agriculture, industry etc to make work: Easier Quicker and More convenient Repairs And Maintenance Of Machines Machines are maintained to function well and last long Preventive Maintenance: This is the care or attention given to a machine to prevent malfunctioning or damage Methods: by washing, cleaning the parts, polishing, greasing and oiling. 2. Predictive Maintenance Corrective Maintenance: This is the care or attention given to a machine to correct simple faults and prevent further damage to total breakdown. Method: by replacement or mending of the damaged parts
Repairs: This is done where preventive and corrective maintenance cannot ne used. At This point the machine has completely broken down. Effect Of Lack Of Maintenance: Rusting Low efficiency Total breakdown DAMS AND ENERGY PRODUCTION A dam: is an artificial barrier usually constructed across a stream or river channel to impound water. Examples Of Dams And Their Locations Kainji dam located in Niger State Shiroro dam located in Niger State Zungeru dam located in Niger State Bakori dam located in SokotoState Asejire dam located in Oyo State Uses of dams in Nigeria Apart from hydro-electric power generation, dams are also used for: Irrigation Water supply.
How Electricity Is Produced From Dam: The hydroelectric power plant generates electricity from dam by harnessing the energy of water released from the reservoir to turn hydraulic turbines which rotate dynamo that would convert electrical energy to electrical developing voltage across the terminals. The power lines transmit the power to consumer within a regional power network. Advantages of Hydro Electrical Power A renewable energy source Cheap and easy to maintain Offers a significant contribution to development etc. Types of Dams Gravity dam Buttress dam Embankment arch To build a dam, the following are to be considered Site testing Site design Site preparation Assignment Describe the working principle of a named hydro electrical power plant