Question

A driver in a car traveling at a speed of
75 km/h sees a cat 125 m away on the road.
How long will it take for the car to accelerate
uniformly to a stop in exactly 122 m?
Answer in units of s.

Answer 1

any clue??

Answer 2

@pooja195 Help me

Answer 3

@pooja195 im new to helping

Answer 4

do u know the answer??

Answer 5

@DylanisNOW u know the answer??

Answer 6

Im trying to get @pooja195

Answer 7

i thuink she offline, but do know the answer to this question??

Answer 8

she appeears to be offline??

Answer 9

yea she offline

Answer 10

Hold on...Im trying to figure it out. Please dont rush!

Answer 11

ok

Answer 12

@pooja195 No she isnt

Answer 13

ok, do u know how to do it though?

Answer 14

Give me a sec please

Answer 15

ok np

Answer 16

@pgpilot326 do u know how to do this? its a physics question

Answer 17

Think of the units.

Answer 18

ok now?

Answer 19

units are 75km/h right?

Answer 20

yes

Answer 21

Wait sorry hold on thats not it thats only 1

Answer 22

ok

Answer 23

75km/h / 125 m=?

Answer 24

600m/h

Answer 25

Okay do you have answer choices?

Answer 26

nopee

Answer 27

do u havea roungh estimate of what the andswer could be??

Answer 28

Think of it like this. Every second the speed decreases by?

Answer 29

We cant give answers...Its just help to get you to understand it!

Answer 30

Think of it like this. Every second the speed decreases by?

Answer 31

the speed decreases by seconds(squared)

Answer 32

Ok that is?

Answer 33

idk.....

Answer 34

.... @pgpilot326 can you help me help him?

Answer 35

Anyways..

Answer 36

dylanis, can u just post a step by step explaination for it

Answer 37

Ok

Answer 38

Step 1:units are 75km/h

Answer 39

Step 2:75km/h / 125=600m/h

Answer 40

Okay now we are at step 3

Answer 41

if a is a constant, integrate to get velocity and again to get position.

the velocity should be linear and the position a quadratic.

Answer 42

since you know the initial and final speed you should be able to calc. the time

Answer 43

pgpilot should we make a equation?

Answer 44

should make 2 equations... velocity and position. you'll need both.

Answer 45

can you please show bothh?

Answer 46

and solve with steps please?

Answer 47

\[v \left( t \right)=v_0+at\]and\[x \left( t \right)=x_0+v_0t+\frac{ 1 }{ 2 }at^2\]

Answer 48

pg you are right good job btw :)

Answer 49

at t=0, initial speed (\(v_0\)) is 75 km/h and initial position is 0 m.
at t=\(t_1\), final speed (\(v_f\)) is 0 km/h and final position is 122 m.

Answer 50

you need to solve for \(t_1\)

Answer 51

ok

Answer 52

how so??

Answer 53

which equation am i putting all this in??

Answer 54

phone, just a minute

Answer 55

\[v \left( t_1 \right)=0=75 +a\cdot t_1\]
\[x \left( t_1 \right)=122=0+75t_1+\frac{ 1 }{ 2 }at_1^2\]

Answer 56

find roots of quadratic in terms of a.

Answer 57

u can handwrite it if u wish, ill prob be able to decode it