Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Projectile Motion - need help

  1. Oct 1, 2007 #1
    1. The problem statement, all variables and given/known data
    a certain airplane has a speed of 180 mi/h and is diving at an angle of 30.0 degrees below the horizontal when a radar decoy is released. The horizontal distance between the release point and the point where the decoy strikes the ground is 2300 ft. (a) How high was the plane when the decoy was released? (b) how long was the decoy in the air?

    2. Relevant equations
    Displacement equations

    3. The attempt at a solution

    I tried converting every distance unit to meters and got the velocity was 80.45 m/s
    and the horizontal vel = 69.67 m/s
    vertical vel = 40.225 m/s

    but then I had to find part b before I could answer part a?

    p.s. the answers I got were a) 1657.67m and b) 22.95 sec.

    i dont think this is right
  2. jcsd
  3. Oct 1, 2007 #2
    oh and 2nd problem

    a) What is the acceleration of a sprinter running at 10 m/s when rounding a bend with a turn radius of 25m? b)In what direction does the acceleration vector point?

    I got a), it's 4 m/s2. But what does b) asking?
  4. Oct 2, 2007 #3


    User Avatar
    Homework Helper

    Your velocity components seems to be correct, but your dropping distance not.

    Show us how you calculated a) with the substituted values. Hint: Use the horizontal speed to calculate the dropping time.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook