The Meaning of Work And Types of Energy

Types of Energy Kinetic Kinetic energy is energy in the form of motion A moving hockey puck has kinetic energy ■ Potential Stored energy or energy not involving motion A car motionless at the top of a hill has potential energy

Work Defined as the transfer of energy through motion. In order for work to take place, a force must be exerted through a distance. To calculate work you multiply the force by the distance (Work=force x distance) The unit of measure for work is the Joule (J)

Work cont. If you push against a car and it doesn’t move, how much work was done? A newton-meter or NM is the same as a joule (J)

Problems A students full backpack weighs 30N. She lifts it from the floor to her desk 1.5m high. How much work was done to lift the pack? A carpenter lifts a 45-kg beam 1.2m. How much work is done on the beam?

Potential vs. Kinetic Energy of a Pendulum Note the drawing on the board

Law of Conservation of Energy Energy can change form, but it cannot be created or destroyed under ordinary conditions. This law applies to closed systems, in which energy cannot enter or leave the system. Mechanical energy of a swing is converted to thermal energy due to friction and air resistance

Assignment Section wrap-up (p. 131) 1-3 Skill Builder