what is the braking distance if travelling 60km/h?

Question

anonymous · Answer

I didnt understand it well !

dumbcow · Answer

braking distance is proportional to speed squared...but you have to look up exact formula

anonymous · Answer

60km / h = 60x1000/3600 = 18.05m/s

anonymous · Answer

what formula am i supposed to use ??

anonymous · Answer

velocity is 18.05m/s

yttrium · Answer

Well, if @dumbcow said it correctly. I think you need to do is to find the square root of your speed. :))

dumbcow · Answer

anonymous · Answer

how can i do that?

yttrium · Answer

You can use your calculator, if you're allowed. :D

dumbcow · Answer

ignore reaction time in formula
$$d = \frac{v^{2}}{\mu g}$$

dumbcow · Answer

oops i forgot 2 in denominator

anonymous · Answer

@Yttrium  your not helpful at all

anonymous · Answer

@dumbcow your a champ

anonymous · Answer

the answer in the textbook is 13.89m however im geting a different answer

dumbcow · Answer

check your conversion....60 km/hr = 16.666 m/s

anonymous · Answer

D=(16.66)^2/2*u*g

anonymous · Answer

???

dumbcow · Answer

it could be a different "u" value...does book say anything about road surface or friction coefficient?

anonymous · Answer

no it doesnt

anonymous · Answer

something is missing from the formula

ganeshie8 · Answer

looks book wants u to use g=10

dumbcow · Answer

yeah and u =1   
thats only way you get their answer

ganeshie8 · Answer

assuming road is concrete, and tyres are rubber

u = 1 between Concrete & Rubber

dumbcow · Answer

the question should have specified those constants for you

anonymous · Answer

it hasnt i hate these textbooks

dumbcow · Answer

using g=10 is not very precise

anonymous · Answer

it should be 9.81 but they should of specified