1 / 9

Drills on Work, Energy and Power

Drills on Work, Energy and Power. 1. A motor does 5,000 joules of work in 20s. What is the power of the motor ? Given: W = 5,000 J, t = 20s Required: P = ? Sol’n : P = P = P = P = 250 P = 250 W.

tillie
Download Presentation

Drills on Work, Energy and Power

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. Drills on Work, Energy and Power

  2. 1. A motor does 5,000 joules of work in 20s. What is the power of the motor? Given: W = 5,000 J, t = 20s Required: P = ? Sol’n: P = P = P = P = 250 P = 250 W

  3. 2. A machine does 1,500 joules of work in 30s . What is the power of this machine? Given: W = 1,500 J, t = 30s Required: P = ? Sol’n: P = P = P = P = 50 P = 50 W

  4. 3. A toaster oven uses 67,500 joules of energy in 45 seconds to toast a piece of bread. What is the power of the oven? Given: W = 67,500 J, t = 45s Required: P = ? Sol’n: P = P = P = P = 1,500 P = 1,500 W

  5. 4. A horse moves a sleigh 1.00 kilometer by applying a horizontal 2,000-newton force on its harness for 2,500 seconds. What is the power of the horse? Given: F = 2,000 N, d = 1,000m, t = 2,500s Required: P = ? Sol’n: P = P = P = P = 800 P = 800 W

  6. 5. Suppose a force of 100 Newtons is used to push an object a distance of 5 meters in 15 seconds. Find the work done and the power for this situation. Given: F = 100 N, d = 5m, t = 15s Required: W = ?, P = ? Sol’n: W = Fd = (100N) (5m) = 500 J P = P = P = 33.33 W

  7. 6. Emily’s vacuum cleaner has a power rating of 200 watts. If the vacuum cleaner does 360,000 joules of work, how long did Emily spend vacuuming? Given: P = 200 W, W = 360,000 J Required: t = ? Sol’n: P = t = t = t = 1,800 s

  8. 7. A force of 100 newtons is used to move an object a distance of 15 meters with a power of 25 watts. Find the work done and the time it takes to do the work. Given: F = 100 N, d = 15m, P = 25 W Required: W = ?, t = ? Sol’n: W = Fd = 100 N (15m) = 1500 J t = t =

  9. 8. What is the power of cart having a mass of 25kg and has an acceleration of 30m/ in a period of 30s covering a distance of 100m? Given: m = 2,500kg, a = 30m/, t = 30s, d= 100m Required: P = ? Sol’n: F = ma = 25kg (30m/) = 750 N W = Fd = 750 N (100m) = 75,000 J P = =

More Related