Simple speed question...?

Question

Assume the brakes in your car create constant "deceleration:, i.e., a constant slowing down, regardless of how fast you were going. If you double your speed, the time required to stop is doubled and the distance to stop is:

a. doubled
b. tripled
c. quadrupled
d. halved
e. none of these

Thanks sooo much for the help. It is appreciated! :)

Answer 1

distance = velocity * time
thus, we can represent the original equation as
d = vt

for the new speed, we get new distance and new time to stop
, let
d' = new distance
v' = new velocity
t' = new time

d' = v' t'
and we know that v' is twice the original speed
thus v' = 2v
and the new time required to stop is doubled, thus
t' = 2t

thus, new distance
d' = 2v 2t
d' = 4vt (and d = vt)
thus
d' = 4d
thus the new distance to stop is quadrupled

Answer 2

) Do you ever speed? Yeah sometimes 2) What do you feel are the biggest dangers of speeding on highways? you don't have as much time to react to a situation 3) What are your largest concerns of speeding on highways? {Not necessarily the same thing as your views on the dangers.} More Deaths 4) How often do you speed? Not sure 5) What is your age? 21 6) How long have you had your drivers license...or do you have one at all? 5 years 7) Have you ever received a traffic ticket? yes 8) Have you ever been stopped for a traffic violation? Speeding 9) Are you male or female? female 10) Do you wear a seatbelt? Not usually 11) Do you ever drive impaired? No 12) Do many things distract your driving? No 13) If yes to above; then what are a few of your common distractions? 14) Do you commonly drive alone or with friends? Alone 15) Do you speed more if you are alone or if you have passengers? Both it dosn't matter 16) How many "close calls" (to accidents) have you had due to speeding in one month? None 17) Do you find that other drivers commonly drive more recklessly/dangerously than you? yes 18) At what time of day do you speed the most? morning and night {Afternoon, night, or times...whatever.} 19) Do you feel you have "control" of your vehicle and could handle any dangers that you may face? Yes 20) What is one comment you have about the way you feel speeding on highways effects or concerns you? It effects how my whole day goes!

Answer 3

I would say e. none of these for this reason:

s = ut + 1/2 at^2 is the formula for the distance.

So, if t is doubled, we have

S = 2ut + 1/2 a4t^2

S = 2 ut + 2at^2

It is neither double, triple or quadrule. Nor half.

Answer 4

Quadrupled. Since the time is doubled, and you are going twice as fast, you will go four times as far.

Answer 5

v=-@t+vo and
d=-1/2@t^2 +vot
so t to stop = vo/@ is doubled
d= 1/2 vo^2/@ (c)

Answer 6

tripled i think but thats really a confusing question

Answer 7

well it would be half of the distance, so d.

Answer 8

C.