Question

A car travels at a uniform acceleration over a distance of 440.0 m. Its final velocity after 20.0 s is 33.0 m/s. What is its initial velocity?

0.0 m/s, 11.0 m/s, 22.0 m/s, or 8.7 m/s

**Not sure how this one goes! :( thank you!

Answer 1

WHat equation will u use here ?

Answer 2

it's one of the ones you wrote earlier right?

Answer 3

is it the v=u+gt?

Answer 4

Yes....what quantities are given in the question ?

Answer 5

Time is not given !

Answer 6

initial velocity=0
final velocity=33
distance=440
time=20 s ?

Answer 7

this may be handy

http://www.studyphysics.ca/newnotes/20/unit01_kinematicsdynamics/chp04_acceleration/images/formulas.GIF

Answer 8

oh so would it be 0.0 m/s ? or not sure if i got those values right? :/

Answer 9

How time is 20s ?
Recheck

Answer 10

not sure :/

what does it mean when it says "final velocity after 20.0 s" ? that's not the total time then?

and @jim_thompson5910 which one applies here? :/ not sure, but i really need to memorize all of those!!

Answer 11

you need to find what piece of info you don't have (and that you aren't solving for)

then use the chart to locate the X that corresponds to that variable to get the correct formula

Answer 12

okay:)

so vf=final velocity=33 m/s ? would that be the final? not sure:(

Answer 13

"A car travels at a uniform acceleration over a distance of 440.0 m. Its final velocity after 20.0 m is 33.0 m/s. What is its initial velocity?"

you want to find vi

you aren't given the time t, so look for the formula with an X under t to get the formula you need

Answer 14

use \(\sf \large s = \frac{1}{2} (v_f-v_i) \times t\) then solve for what you're looking for

Answer 15

oh is that 20 s and not 20 m?

Answer 16

I see now

Answer 17

Yes i think so..its 20s

Answer 18

you aren't given the acceleration and you don't need to solve for that

so look for an X under the acceleration 'a' to get your formula

Answer 19

oops my bad :P typed in m instead of s

sorry you guys!!!

Answer 20

so d=1/2(vf+vi)t ?

Answer 21

Now u'll hv to calculate a first..

Answer 22

d=1/2(vf+vi)t
d=distance=440
vf=33
vi=?
t=20
so 440=1/2(33+x)20
440=1/2(660+20x)
440=330+10x
110=10x
x=11 ?

Answer 23

ye boy

Answer 24

u'll have to use 2nd equation to calculate a first. Then u can calculate u from first equation.

Answer 25

11 m/s looks good

Answer 26

haha woohoo!! yay! :)

thanks so much!!

and sorry again for my typo!! will triple check from now on! hehe :)

Answer 27

that is your initial velocity, boy!

Answer 28

do you want to learn how to derive that or what?

Answer 29

i'd like to know how to derive that nin

Answer 30

memorizing formula is easy, but knowing how to get the formula is better

Answer 31

fifty bucks, @raffle_snaffle I already helped you in modern physics for free :P

Answer 32

LOL fifty bucks?