1 / 8

The Work-Energy Theorem and Kinetic Energy

The Work-Energy Theorem and Kinetic Energy. 6.2. Work-Energy Theorem. Do work means  W = Fs F = ma So work gives an object some acceleration Acceleration means the velocity changes. Derivation of Work-Energy Th. F = ma Fs = mas v f 2 = v 0 2 + 2 as  solve for as

layne
Download Presentation

The Work-Energy Theorem and Kinetic Energy

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. The Work-Energy Theorem and Kinetic Energy 6.2

  2. Work-Energy Theorem • Do work means  W = Fs • F = ma • So work gives an object some acceleration • Acceleration means the velocity changes

  3. Derivation of Work-Energy Th. • F = ma • Fs = mas • vf2 = v02 + 2as solve for as • as = ½ (vf2 – v02) • Fs = m ½ (vf2 – v02) • W = ½ mvf2 – ½ mv02

  4. Kinetic Energy • Energy due to motion • If something in motion hits an object, it will move a some distance • KE = ½ mv2 • Scalar • Unit is joule (J)

  5. Work-Energy Theorem • Net external force = change in kinetic energy

  6. Example 1 • A 0.075-kg arrow is fired horizontally. The bowstring exerts an average force of 65 N on the arrow over a distance of 0.90 m. With what speed does the arrow leave the bow? • 39.5 m/s

  7. Example 2 • A foolish skier, starting from rest, coasts down a mountain that makes an angle of 30° with the horizontal. The coefficient of kinetic friction between her skis and the snow is 0.100. She coasts for a distance of 20 m before coming to the edge of a cliff and lands downhill at a point whose vertical distance is 5 m below the edge. How fast is she going just before she lands? • 10.52 m/s

  8. Practice Work • Do some work on these. • 173 CQ 4 – 8, P 12, 13, 15, 17, 18, 20, 23 • Total of 13 problems

More Related