1 / 10

Energy Notes

Learn about energy, its types, and how it is observed and measured, including Potential Energy and Kinetic Energy equations. Practice problems included for better understanding.

juliabutler
Download Presentation

Energy Notes

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Energy Notes

  2. What is Energy? • Energy is the ability to do work. • Whenever work is done, energy is transformed or transferred to another object or system.

  3. How is energy observed and measured? • We know that work is done only when an object moves, but energy can be present in an object when nothing is happening. • However, energy can only be observed when it is transferred from one object to another. • Like work, energy is measured in joules.

  4. Potential Energy • Potential energy is stored energy. • It is sometimes called energy of position because it results from the positions of the objects.

  5. 3 Types of Potential Energy • There are three types of potential energy. • 1. Elastic potential energy- the energy stored in any type of stretched or compressed elastic material (spring or bungee cord). • 2. Gravitational potential energy- any objects separated by a distance have this because of gravitational attraction between objects. 3. Chemical Potential Energy- energy stored in chemical bonds.

  6. Gravitational P.E. equation • Gravitation P.E. depends on mass and height. • grav. P.E. = mass x free-fall accel x height • Also written as: PE = mgh • Notice that the mg is just the weight of the object, and the h is the distance, so the this is really the force (weight) x distance, which is the equation for work.

  7. Practice • 1. A student holds a 0.055 kg egg out a window. Just before the student releases the egg, it has 8 J of GPE. How far is the student from the ground? • 2. A diver has 3400 J of GPE after stepping on a platform that is 6 m above the water. What is the diver’s mass? • 3. Calculate the GPE in the following: • A. a car with a mass of 1200 kg at the top of a 42 m high hill • B. a 65 kg climber on top of Mt. Everest which is 8800m high. • C. a 0.52 kg bird flying at an altitude of 550 m

  8. Kinetic Energy • Kinetic energy is the energy of a moving object due to its motion. • Kinetic energy depends upon mass and speed, though speed is more important.

  9. Kinetic Energy Equation • The kinetic energy equation is: kinetic energy = ½ x mass x speed squared This also written as: KE = ½ mv2

  10. Practice • 1. Calculate the KE in joules of a 1500 kg car moving at the following speeds: • A. 29 m/s • B. 18 m/s • C. 42 km/h • 2. A 35 kg child has 190 J of KE after sledding down a hill. What is the child’s speed in m/s at the bottom of the hill? • 3. A bowling ball traveling 2 m/s has 16 J of KE. What is the mass of the bowling ball in kg?

More Related