NTNUJAVA Virtual Physics Laboratory
Enjoy the fun of physics with simulations!
Backup site http://enjoy.phy.ntnu.edu.tw/ntnujava/
May 25, 2019, 04:51:42 am *
Welcome, Guest. Please login or register.
Did you miss your activation email?

Login with username, password and session length
 
   Home   Help Search Login Register  
Acting locally and thinking globally. ...Wisdom
Google Bookmarks Yahoo My Web MSN Live Netscape Del.icio.us FURL Stumble Upon Delirious Ask FaceBook

Pages: [1]   Go Down
  Print  
Author Topic: Cross a river with a boat  (Read 4332 times)
0 Members and 1 Guest are viewing this topic. Click to toggle author information(expand message area).
ahmedelshfie
Moderator
Hero Member
*****
Offline Offline

Posts: 954



«
Embed this message
on: March 10, 2011, 06:03:44 pm » posted from:Uberaba,Minas Gerais,Brazil

The applet design by prof Hwang, modified layout by Ahmed.
Original applet Cross a river with a boat

You wish to cross a river and arrive at a dock that is directly across from you, but the river's current
will tend to carry you downstream. To compensate, you must steer the boat at an angle. Find the angle θ, given the magnitude, |vWL|, of the water's velocity relative to the land, and the maximum speed, |vBW|, of which the boat is capable relative to the water.

◊ The boat's velocity relative to the land equals the vector sum of its velocity with respect to the water and the water's velocity with respect to the land,
vBL = vBW+ vWL .

If the boat is to travel straight across the river, i.e., along the y axis, then we need to have vBL,x=0.
This x component equals the sum of the x components of the other two vectors,
vBL,x = vBW,x + vWL,x , or 0 = -|vBW| sin θ + |vWL| .

Solving for θ, we find sinθ=|vWL|/|vBW|,
 so θ =sin-1 |vWL|/|vBW|.

The following simulation let you play with it. Enjoy!

You can adjust the velocity of the river or the boat with slider.
You can also change it's direction (angle θ=c).
It will remember the last 3 traces.

Embed a running copy of this simulation

Embed a running copy link(show simulation in a popuped window)
Full screen applet or Problem viewing java?Add http://www.phy.ntnu.edu.tw/ to exception site list
Press the Alt key and the left mouse button to drag the applet off the browser and onto the desktop. This work is licensed under a Creative Commons Attribution 2.5 Taiwan License
  • Please feel free to post your ideas about how to use the simulation for better teaching and learning.
  • Post questions to be asked to help students to think, to explore.
  • Upload worksheets as attached files to share with more users.
Let's work together. We can help more users understand physics conceptually and enjoy the fun of learning physics!


* Cross a river with a boat.jpg (27.7 KB, 655x406 - viewed 361 times.)
Logged
Pages: [1]   Go Up
  Print  
Acting locally and thinking globally. ...Wisdom
 
Jump to:  


Related Topics
Subject Started by Replies Views Last post
How can a boat sail upwind?
Dynamics
Fu-Kwun Hwang 1 19866 Last post February 11, 2011, 04:00:38 pm
by darlenehill19
C=AXB cross product vector relations
misc
Fu-Kwun Hwang 0 22066 Last post February 23, 2007, 08:45:08 pm
by Fu-Kwun Hwang
Satcom Cross-polarization of V / H
Electromagnetics
audioviking 1 12236 Last post October 28, 2009, 03:55:25 pm
by Fu-Kwun Hwang
C=AXB cross product vector relations
misc
ahmedelshfie 0 6641 Last post May 21, 2010, 02:02:32 am
by ahmedelshfie
Cross a river with a boat
Kinematics
Fu-Kwun Hwang 4 32029 Last post July 12, 2016, 12:16:16 am
by rockmanx4
Powered by MySQL Powered by PHP Powered by SMF 1.1.13 | SMF © 2006-2011, Simple Machines LLC Valid XHTML 1.0! Valid CSS!
Page created in 0.048 seconds with 25 queries.since 2011/06/15