Ask Me Help Desk

Ask Me Help Desk (https://www.askmehelpdesk.com/forum.php)
-   Physics (https://www.askmehelpdesk.com/forumdisplay.php?f=258)
-   -   Relative speed (https://www.askmehelpdesk.com/showthread.php?t=332745)

  • Mar 23, 2009, 08:21 AM
    gaboonviper04
    Relative speed
    A boat which travels at 2.5 km per hour relative to the water aims straight for the opposite bank of a 84.4 m wide river. If it reaches the opposite side 253.2 m downstream, what is the speed of the river?
  • Mar 23, 2009, 08:29 AM
    Perito

    The speed of the river adds to, or subtracts from, the speed of the boat. You should be able to solve the problem with that information.

    Split the problem into two components -- a cross-stream component and a downstream component. Solve the problem that way.
  • Apr 14, 2009, 02:41 PM
    mdoble
    7.5 km/hr

    2.5 km/hr = 41.66 m/m relative to the river (frame of ref)

    to travel 84.4 m at that speed takes 2.0256 min

    in 2.0256 min the river has traveled 253.2 m

    125 m/min = 7500 m/h = 7.5 km/h


    malcolm

  • All times are GMT -7. The time now is 07:18 PM.