Expert: Azeem Hussain - 5/31/2009

Question
QUESTION: "My name is Kira Yuta I am in grade eleven in USA

I am studying for my final exam and I came a upon this questions I do not understand. I hope you can help me

I do not understand Part B questions (1,2 and 3) on this page:

http://education.alberta.ca/media/930712/03%20pure30%20feb-09%20skydiving%20stud


please show me how to do this questions step by steo I understand I am asking alot but please help me out

ANSWER: Hello Kira,

What you need to understand in order to solve the question is written immediately before the question.

For question 1, use v_t=g/k and plug in the values of k to solve for the terminal velocities.

For question 2, the terminal velocity is inversely proportional to the k value.  As k increases, v_t decreases, and vice-versa.

For question 3, plug t=12 into the equation and solve for v.

These questions are straightforward.  Be sure to read them over a few times along with the theory that comes before them before solving them.

Thanks for asking,
Azeem

---------- FOLLOW-UP ----------

QUESTION: Oh ok thank you
I did not read the equation right
but how would you do part B question 4

Answer
Hi Kira,

"98% of its terminal velocity" means v=(0.98)45=44.1.  Plug this into the equation and solve for t.
v=45[1-(0.804)^t]
44.1=45[1-(0.804)^t]
44.1/45=1-(0.804)^t
0.98=1-(0.804)^t
0.804^t=0.02
log0.02/log0.804=t
t=17.93

ANSWER: The required time is 17.93 seconds.

Thanks for asking,
Azeem