WebAssign.net    Info   Guide   Change Password   Student Surveys   Textbook   Credits  Logout 
 
 Name: Scott Bonham
 School: NC STATE
 Course: PY 101, section 1, Spring 2001
 Teacher: Scott Bonham
 Due Date: Friday, Jun 08 2001 12:54 PM EST
 Current Date: Monday, Jan 08 2001 4:34 PM EST
  
 

  

  

   

Incline

1.

Statement of the problem

You are visiting Pittsburgh with your family, and take a ride on one of the city's historic tourist attractions, the Duquesne Incline. Originally built to transport workers between steel mills along the river and homes on the hill above it, it is now a historical site and a convenient way to get to a series of scenic overlooks with a view of the city. The incline, which you happened to have read about on the the Incline's web site, (local) consists of two cable cars rolling on straight, steep rails, connected by a pair of cables running up to the station at the top, over a drum that pulls the cables, and back down to the other car (photo). One thing you don't recall reading about is the weight of the car, so you get wondering about it. The web site does mention the average working tension of the cables, and you figure a typical load is ten passengers and you can ignore friction, so from that information you decide to estimate the mass of the car.

Gather

Given information: Fill out this table with information from text and the web site:
QuantityGiven unitsUnits for calculation
slope of trackgrade %angle °
average speed of car ft/min m/s
Number of people
Number of cables connecting to a car
tension per cable ("operating strain")
% of maximum tons		 tons N

Estimate: estimate reasonable values for quantities not given but needed to solve the problem. (The computer will accept a range of reasonable values, which you must use in subsequent calculations.)
Quantity Estimated value
Mass of average passenger kg
Mass of all passengers kg

Organize

Principles: mark the following principle(s) that apply to this problem:

Draw Draw a free-body diagram of the forces on the car you rode in. You probably will find it useful to switch back and forth between the XY (rectangular) and rotated XY coordinates; the rotation angle has been set to the correct angle.
">

Analyze

Calculate: Calculate the following quantities:
total tension force on car with passengers N
weight of car with passengers N
weight of car without passengers N
mass of car kg

Learn

Reflection questions:
The mass of an average load of passengers is about what fraction of the mass of the car and passengers combined.

If we didn't ignore friction, what would its effect be?




Principles in incorporate.

Submit for Grading


Return to Assignments Summary