NASA Logo - Web Link to NASA.gov Vertical Line

+ Text Only Site
+ Non-Flash Version
+ Contact Glenn

Go
ABOUT NASA NEWS AND EVENTS MULTIMEDIA MISSIONS MyNASA WORK FOR NASA


Energy Activity Answers


  1. A model glider has a mass of 1 kg. How much potential energy does it have 2 meters off the ground?
    Ep = mgh = (1)(9.8)(2) = 19.6 j
  2. The same model has a velocity of 2.2 m/s. How much kinetic energy does it have?
    Ek = 1/2(m)V2 = (1/2)(1)(2.2)2 = 2.42 j
  3. If the same model descends 2 meters and all it's potential energy is converted to kinetic energy, what is the glider's change in velocity?
    Ek = 1/2(m)U2

  4. A full-sized glider has a weight of 4,900 N, while it's pilot has a weight of 825 N. If it is 1,000 meters off the ground, how much potential energy do the plane and pilot have?
    Ep = mgh or Fwh = (4,900 + 825)(1,000) = 5,725,000 j
  5. The same glider from Problem 4 has a velocity of 35 m/s. How much kinetic energy does it have?
    Ek = 1/2(m)V2 = 1/2 [(4.900 + 825)/9.8](352) = 357,813 j
  6. The same glider from Problem 4 has a velocity of 35 m/s. The glider descends 900 meters. What is it's new velocity?
    Ep = Fwh = (4,900 + 825)(900) = 3.63825 * 109 j

    New Vel. = Old + Change = 35 + 132 = 167 m/s
  7. Compare the velocity you calculated in Problem 6 to the speed of sound. Is this answer reasonable? Why or why not?
    167/346 = .48 Approximately 1/2 the speed of sound. (Note: This speed is faster than a B-17 Flying Fortress.)


Related Pages:
Standards
Activity
Worksheet
Lesson Index
Aerodynamics Index

 

     First Gov Image


+ Inspector General Hotline
+ Equal Employment Opportunity Data Posted Pursuant to the No Fear Act
+ Budgets, Strategic Plans and Accountability Reports
+ Freedom of Information Act
+ The President's Management Agenda
+ NASA Privacy Statement, Disclaimer,
and Accessibility Certification

 

NASA Logo   
Editor: Tom Benson
NASA Official: Tom Benson
Last Updated: Thu, Jun 12 04:46:38 PM EDT 2014

+ Contact Glenn