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Homework Help: Constant acceleration problem involving NASA exploration vehicle.

  1. Jan 11, 2009 #1
    1. In Jan. 2004, NASA landed exploration vehicles on Mars. Part of the descent consisted of the following stages:?
    Stage A: Friction with the atmosphere reduced the speed from 19300 km/h to 1600 km/h in 4.0 min.
    Stage B: A parachute then opened to slow it down to 321 km/h in 94 s.
    Stage C: Retro rockets then fired to reduce its speed to zero over a distance of 75 m.
    Assume that each stage followed immediately after the preceding one and that the acceleration during each stage was constant.

    1.Find the rocket's acceleration (in m/s^2 ) during stage C.

    2.What total distance (in m} did the rocket travel during stage A?

    3.What total distance (in km) did the rocket travel during stage C?

    V1= V0 + a1T
    x-x0= V0T + 1/2a1T6
    (V1)^2- (V0)^2 = 2a1(T^2)(x-x0)
    a1= acceleration T=time Vo=initial velocity x,x0= position, initial position

    The last question isnt that just 75 m converted to KM? I put that in and I got the answer wrong. Also for #1 I got -0.05 and I got that wrong too. And for #2 I got 356m and got that wrong too. I used the above equations to get all of these answers. What am i doing wrong? Please Help. Thanks
  2. jcsd
  3. Jan 11, 2009 #2


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    Homework Helper

    Hi fuhgidabowdit,

    Looking at #1, how did you get -0.05 (and what numbers did you use to get it)?
  4. Jan 11, 2009 #3
    hey thanks for replying. I figured out what I was doing wrong. It was just some stupid algebraic mistakes.
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