1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Rate of change

  1. May 12, 2013 #1
    I am trying to complete the following question:

    By pumping the air pressure in a tank is reduced by 15%/second. The percentage of air pressure remaining is fiven by the formula.


    Plot p against t for 0 < t < 30s.

    Deternine the rate of change at 5s & 10s. I have plotted the graph.

    Verify you anser via calculus.

    Can anyone please advise which formula is applicable to this?
  2. jcsd
  3. May 12, 2013 #2
    The rate of change is given by the derivative p'(t)=dp/dt where t is the argument(given in seconds). Your are interested in the rate of change at after 5s and 10s, hence you want to calculate p'(5) and p'(10).

    You have plotted the graph so you could also find the slope of the tangent(2 lines) at t=5 and at t=10. But the first method is much easier if you know how to differentiate that function.
  4. May 12, 2013 #3
    thank you, that makes sense.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted