Question

Ann is driving down a street at 59 km/h.
Suddenly a child runs into the street.
If it takes Ann 0.765 s to react and apply
the brakes, how far will she have moved before
she begins to slow down?
Answer in units of m

Answer 1

Start by converting the 59 km/h to km/s.

Answer 2

How do you do that? @gypsy1274

Answer 3

How many minutes in an hour?
How many seconds in a minute?

Answer 4

60 minutes in an hour and 60 seconds in a minute @gypsy1274

Answer 5

1 hour \(\times\) 60 minutes \(\times\) 60 seconds

Answer 6

FYI: you don't need to tag me, since I have already posted a reply, I will get a notice when anyone posts another reply.

Answer 7

oh sorry and its 3,600

Answer 8

Now set up a proportion. The speed per second on one side.

Answer 9

how do i do that?

Answer 10

\(\dfrac{km}{seconds} = \dfrac{km}{seconds}\)
The first fraction could be the driving speed.
What you don't know is how far she will travel - that can be represented by x.

Answer 11

would it be \[\frac{ 59 }{ 0.765 }=\frac{ x }{ 0.765 }\]

Answer 12

Almost. Remember that 59km is per hour or 3600 seconds.
Make that correction, then cross multiply.

Answer 13

\[\frac{ 3600 }{ 0.765 }=\frac{ x }{ 0.765 } answer is 36000\]

Answer 14

@gypsy1274

Answer 15

@chmvijay can you please help me?

Answer 16

57 km/h/3600 s/h=.0158333 km/s=15.83 m/s
15.83 m/s x .765 s= 12.1125 m..

Answer 17

the answer is 12.1125m/s? @CHM

Answer 18

@chmvijay

Answer 19

@Hero is the answer 12.1125m/s

Answer 20

that was the wrong answer @chmvijay

Answer 21

Online question for hw

Answer 22

how do u assure that i solved one is wrong ?

Answer 23

because it said incorrect @ch

Answer 24

ok ok fine

Answer 25

would the answer be 3600m

Answer 26

14000

Answer 27

i just crossed multiplied\[\frac{ 3600 }{ 0.765 }\times \frac{ x }{ 0.765 }\]

Answer 28

answer 3600 is that right?

Answer 29

@chmvijay

Answer 30

IDK

Answer 31

@satellite73 @dumbcow @kropot72 @robtobey @radar @timo86m @dan815 @Luigi0210
cn u answer this question :)

Answer 32

@chmvijay , you did it correctly but you misread the speed ....its 59 km/hr not 57 :)

Answer 33

but though it wont make so much different in answer right right and she said "my answer is showing wrong in online test"

Answer 34

0.8 seconds? That baby dead...

Answer 35

haha someone was texting and driving

Answer 36

@JazminZamarripa
\[\frac{59 km}{hr}*\frac{1 hr}{3600 \sec}*\frac{1000 m}{1 km} = \frac{16.388 m}{\sec}\]
multiply by .765 sec to gave distance in meters car travels

Answer 37

Thank you so much:) @dumbcow

Answer 38

no @abb0t that baby is still alive :P

Answer 39

yw

Answer 40

hey thank you @dumbcow

Answer 41

Thank you too @chmvijay

Answer 42

yw :)