Study with the several resources on Docsity
Earn points by helping other students or get them with a premium plan
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
Here you can find a complete lecture series on Engineering Physics course. These lecture slides includes: Power, Energy Per Unit Time, Energy Accounting, Dissipative Forces, Friction, Falling Co Ee Lter, Air Resistance
Typology: Slides
1 / 25
This page cannot be seen from the preview
Don't miss anything!
The world record for a dragster for a standing quarter-mile (402. m) is 4.428 seconds as of Sept 15, 2008. Let’s neglect air friction and assume that the acceleration was constant. Given: g = 9.8 m/s and the dragster’s mass: m=1983 kg, what was the dragster’s aver- age output power? (A) md 2 /t^3 (B) 2md/t^3 (C) md/2t^3 (D) md^2 /2t^3 (E) 2md^2 /t^3
ANSWER: We are given the distance d = 402.3 m, t = 4.428 s, and m = 1983 kg. Power P = work/time = Fd/time (for constant force F) By Newton’s 2nd Law, F=ma. Therefore, P = mad/t. For constant acceleration x = (1/2)at^2 , so a = 2d/t^2 (where x=distance d) Therefore P = m[2d/t 2 ]d/t = 2md^2 /t^3 docsity.com
Ef = Ei + W
Ef = Ei + W Kf = Ki + W
Ef = Ei + W
Ef = Ei + W Kf + Uf = Ki + Ui + W
