**Unit 5: Work, Energy and
Power**

**Problem Set C**

**Problem 7: **

Esteemed Chinese ski jumper, Li Ping Phar, leaves the jump ramp with an initial speed of 33.1 m/s and a height (relative to the bottom of the ski hill) of 56.2 meters. She encounters -7624 Joules of work due to air resistance during her flight through the air. Determine the speed (in m/s) of her 45.2-kg body the instant prior to striking the ground at the bottom of the hill.

- Read the problem carefully and diagram the physical situation (initial-final state diagram and/or work-energy bar chart)
- Identify known and unknown information in an organized manner (write on diagram)
- Take the time to plot out a strategy prior to beginning the solution (cancel terms in work-energy equation and perform conversions when necessary)
- Identify an appropriate formula to use
- Perform step-by-step algebraic manipulations

**0.5 • m • v _{i}^{2
}+ m • g • h _{i} + F • d • cos
_{ } =
0.5 • m • v_{f}^{2 }+ m • g • h
_{f}**

General information about work and energy problems is described on the Set C Overview page.

A detailed discussion of how to analyze physical situations using work-energy bar charts is provided online at The Physics Classroom.

A detailed description of the work-energy relationships for situation in which external forces are doing work is provided online at The Physics Classroom.

Audio Help for Problem: 1 || 2 || 3 || 4 || 5 || 6 || 7 || 8 || 9 || 10 || 11 || 12 || 13 || 14

Retrieve info about: Audio Help || Technical Requirements || Usage Policy || CD-ROM

Return to: Physics 163 Problem Set Page || Physics 163 Home Page