EEEYassin imwt 1479 introduction to mechanical power transmission
- 2. •Mechanical advantage is the ratio between the output force and input force. It is also the ratio between the input distance and the output distance. •MA = output force/input force. •MA = input distance/output distance. •A compound machine is a machine that combines two or more simple machines.
- 3. •Force: Forces can be described as a push or pull on an object . •They can be due to phenomena such as gravity, magnetism, or anything that might cause a mass to accelerate . •In physics, a force is any interaction that, when unopposed, will change the motion of an object. •Newton's first law says that an object will remain at rest or will continue to move in a straight line unless it is acted on by a net force.
- 4. • Energy: Energy is the ability to do work. • Energy comes in different forms: * Heat (thermal) * Light (radiant) * Motion (kinetic) * Electrical * Chemical * Nuclear energy *Gravitational • People use energy for everything from walking to sending astronauts into space. • There are two types of energy: • Stored (potential) energy • Working (kinetic) energy • For example, the food a person eats contains chemical energy, and a person's body stores this energy until he or she uses it as kinetic energy during work or play.
- 5. • Mechanical energy is the sum of kinetic and potential energy in an object that is used to do work. In other words, it is energy in an object due to its motion or position, or both. • There are two forms of mechanical energy: potential energy and kinetic energy. 1. Potential energy is the stored energy of position due to the vertical position of an object within Earth's gravitational field and is calculated using the equation: PEgrav = m•g•h • where m is the mass of the object (with standard units of kilograms), g is the acceleration of gravity (9.8 m/s/s) and h is the height of the object (with standard units of meters) above some arbitrarily defined zero level (such as the ground or the top of a lab table in a physics room). 2. Kinetic energy is defined as the energy possessed by an object due to its motion. The equation for kinetic energy is: KE = 0.5 • m • v2 • where m is the mass of the object (with standard units of kilograms) and v is the speed of the object (with standard units of m/s). • The total mechanical energy possessed by an object is the sum of its kinetic and potential energies.
- 6. •Work: Work results when a force acts upon an object to cause a displacement (or a motion) or, in some instances, to hinder a motion. •Power is the rate at which work is performed. •Power transmission is defined as the transfer of energy from its place of generation or storage to a location where it does work. •Example: Electrical energy is stored in a battery; it is then transmitted through wires to a motor where it is converted into mechanical energy to do work.