Question

an automobile accelerates from rest at 1+ 3* sqrt (t) mph/sec for 9 seconds.
What is the velocity after 9 seconds?

Answer 1

1+3sqrt(9)
1+3(3)
1+9
10mph

Answer 2

^ Wouldn't this find the acceleration at time t, not the velocity?

Answer 3

*time 9s

Answer 4

Good point Xishem... I wondered about that too, but I can't tell from the question X(

Answer 5

Would integrating the function from 0 to 9 give the correct answer?

Answer 6

yes

Answer 7

Hm, when the problem states it like that... does it mean that the velocity is the function 1 + 3*(t) or the acceleration?

Answer 8

the function is of acceleration

Answer 9

so its integral will be velocity

Answer 10

It means acceleration....yeah, Xishem, you're right, this will require integration

Answer 11

Yeah, the book says mph/sec..
how should it be stated if it was giving the velocity?

Answer 12

(t+6t^(3/2)) from 0-->9

Answer 13

i would change either the hours to seconds or vice versa

Answer 14

so your answer can be in the form mps or mph

Answer 15

this can be done by dimensional analysis

Answer 16

i get v(t) = t + 2t*sqrt(t)
v(9) = 9 +2*9*sqrt(9) = 63 mph

Answer 17

integral of sqrt (t) = [2t^(3/2)]/3
Multiply that by the 3 constant.. = 2t^(3/2)
am I doing something wrong? I can't get sqrt (t)

Answer 18

it's the same thing... 2t*t^(1/2)=2t^(3/2)

Answer 19

Oh I see. I would have never though of to do that... makes calculations so much easier, haha.