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Homework Help: What next Im stuck?

  1. Nov 27, 2006 #1
    a car pulling 20,000pounds accelerate uniformly from a rest to a speed of 40 miles/hour in 12 seconds

    (a) find the distance (infeet AND miles) that the car travels during this time

    (b) find the constant acceleration in ft/s^2 of the car

    part a i get 480 feet is this correct i then divide it by 5280 to get it in miles

    then i finding the constant acceleration

    do i do a=delta(v)/delta(t)
  2. jcsd
  3. Nov 27, 2006 #2
    For part a) how did you end up getting feet first? Your velocity was given in miles, so any formula you use involving vecocity should use miles somewhere. Unless you convert from miles to feet beforehand, which is just extra work for yourself because you will have to convert it back to miles afterwords (as they ask for an answer in miles too).

    I don't actually use miles and feet (I use Kilometers and meters), so if you'd like me to check your answer you're going to have to show your work. 1 feet = how many miles? 1 mile = how many feet? I think your teacher/professor wants you to actually be able to figure it out, instead of memorizing 52.. whatever.
    Last edited: Nov 27, 2006
  4. Nov 28, 2006 #3
    a is asking for both feet and miles, so i guess your learning conversion units. For the constant acceleration, it is dv/dt, so it should be v-v0/12-0
    but remmeber acceleration should be in m/s^2 not miles/hour
    convert them.
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