Question

Okay, I have no clue what I am doing wrong. I've been following part a of this http://www.webassign.net/latex2pdf/2a2176c1f300dcc09b8a130c84af8595.pdf solution to help me with part a of this question I'm stuck on: If a rock is thrown upward on the planet Mars with a velocity of 18 m/s, its height (in meters) after t seconds is given by H = 18t − 1.86t^2. Find the velocity of the rock after two seconds. No matter what I do, it's still the wrong answer and it's becoming really frustrating considering that notes that my professor gave my class doesn't help with this at all.

Answer 1

...

Answer 2

im sry. only 13. I can try u know, being asian and all but no garentees.

Answer 3

maybe just sub in 2 for t

Answer 4

did u include direction? velocity is direction and speed.

Answer 5

28.56 m/s upward?

Answer 6

There's no direction at all. it has to be found the same way as the answer was found is the solution pdf I posted. This question has to be found the same was as that of solution a.

Answer 7

.

Answer 8

perhaps set ur limit to 2?

Answer 9

I think u need to use derivative.

Answer 10

try 10.56. if correct, i'll tell u why.

Answer 11

hello?

Answer 12

you have to find v(2)

Answer 13

did she just leave?

Answer 14

i think she just ditched which means eiither I got it right... or I MESSED UP AND SHE MAD.

Answer 15

I left because you weren't helping me at all with what you were suggesting and was adding to my frustration. And surjithayer, I knew I had to find v(2), that's the whole point of the question but I was struggling with trying to get the correct answer.

Answer 16

\[\frac{ dH }{ dt }=18-2*1.8t=18-3.6t\]
when t=2
v=18-3.6*2=18-7.2=10.8 m/s

Answer 17

it is not 1.8 ,it is 1.86
2*1.86=3.72
when t=2
v=18-3.72*2=18-7.44=10.56m/s