AERONAUTICAL LECTURING NOTES

What is machine? A machine is any device which reduces human effort by using mechanical parts and concepts. In what are the ways we use machines? Give examples too. 1.     Machines are used to transform energy- Generator 2.     Machines are used to transfer energy from one place to other – Crank shaft 3.     Machines are used to multiply the energy- Pulley 4.    Machines can be used to multiply speed- Bicycle 5.     Machines can be used to change the direction of a force – Flag hoist What are the simple machines available? 1.     Lever 2.     Pulley 3.     wheel and axle 4.     inclined plane 5.     Screw 6.    Gear

Define energy. Energy is the capacity to perform a given task. Energy can be either potential or kinetic. Define Potential energy Potential energy can be the energy at rest or energy stored in body. Potential energy may be classified into three groups:  (1) Due to position – E.g. Water in an elevated reservoir (2) Due to distortion of an elastic body- E.g. compressed spring (3) Work through chemical action- E.g. Energy stored in fuel To calculate potential energy due to position, we use the formula Potential Energy = Weight × Height (N-m or Joule) Define kinetic energy. Kinetic energy is defined as the energy in motion. Running train, flying aircraft and all dynamic objects will posses this energy. Kinetic Energy = 1 ⁄ 2 Mass × Velocity 2