1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Time for a bomb to hit the ground

  1. Feb 23, 2008 #1
    1. The problem statement, all variables and given/known data
    Bush fir patrols sometimes drop small bomb to start a controlled burn off from aeroplanes. Peter was flying his over a forest at constant horizontal speed of 75m/s and at contsant altitude of 490m when he dropped the bomb.
    A) how long does it take for the bomb to hit the ground?

    2. Relevant equations
    we have a displacement (490m) , an acceleration (gravity, 9.8 m/s/s) and a velocity (75m/s), so v = u + at could be transposed to give time, however im hopeless at this. please advise..
    3. The attempt at a solution
    after some fiddling around with other formulae such as t = s/v = 6.53 s.. which according to the answers section is wrong.. they say 10s.. is this right? please advise me on this ASAP please..
     
  2. jcsd
  3. Feb 23, 2008 #2
    Welcome To PF.

    When the bomb is dropped from the aeroplane it has some horizontal velocity which is equal to the velocity of the aeroplane i.e. 75 m/s.
    Use concepts of horizontal and vertical components of velocity.Use accln along x axis=0 and accln along y-axis = g.Use s[y]: 490 m.

    Now use simple kinematic equations.

    suggestion= the simple basic formulae are very important but in these kinda questions they will not be aplicable becoz as there are horizontal and vertical components of velocityand accln involved.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?