lecture17_notes - v ~ 20 m/s(~45 mi/h P ~ 1340 W(~1.8 hp...

Info icon This preview shows pages 1–16. Sign up to view the full content.

View Full Document Right Arrow Icon
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
A cyclist travels along a flat road at constant speed v. The power produced by the cyclist all goes to overcoming air drag . How does the power the cyclist must produce to travel at 54 km/h compare with that required to travel at 27 km/h ? P(54 km/h)/P(27 km/h) = ? A. 1 B. 2 C. 4 D. 8 E. 16
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Power and Energy in Cycling Assume P cyclist Drag force × velocity (P = Dv) P cyclist = 1/2 C ρ A v 2 × v = 1/2 C ρ A v 3 Assume C~ 0.4, r = 1.2 kg/m 3 , A~0.7 m 2 Assume human body ~ 25% efficient in converting food energy into mechanical energy. 1 Cal =4.2 J, 1 food Calorie =1 kCal = 4,200 J
Image of page 4
Prof. Liepe: v ~ 8 m/s (17 mi/h) P ~ 86 W (~0.12 hp) Burns ~ 344 W, 1.24 MJ/hour, 295 kCal/hour Professional distance cyclist: v ~ 14 m/s (~30 mi/h) P ~ 460 W (~0.6 hp) Burns ~1.8 kW, 6.6 MJ/hour, 1580 kCal/hour Professional sprint cyclist:
Image of page 5

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 6
Image of page 7

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 8
Image of page 9

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 10
Image of page 11

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 12
Image of page 13

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 14
Image of page 15

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 16
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: v ~ 20 m/s (~45 mi/h) P ~ 1340 W (~1.8 hp) Burns ~ 5.4 kW, 19 MJ/hour, 4600 kCal/hour Average daily food energy intake for Tour de France Cyclists: ~10,000 kCal/ day (~7 lb of uncooked pasta) Which of the following forces are conservative forces? A. Gravity B. Spring force C. Friction D. two of the above E. three of the above A mass m is connected to a rigid massless rod of length L . The mass is released from the vertical as shown. What is its speed v at the bottom of its motion? m +y L v = ? A. gL B. (gL) 1/2 C. (2gL) 1/2 D. (4gL) 1/2 A block of mass m is released from the top of the frictionless track shown. What is its speed v at the top of the loop-the-loop? R h v = ? A. 2gh B. (2gR) 1/2 C. [2g(h-R)] 1/2 D. [2g(h-2R)] 1/2...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern