PHYSICS - Calculating the Braking Distance of a Car (Exam Question Example)

PHYSICS - Calculating the Braking Distance of a Car (Exam Question Example)

Fun example showing two different takes at essentially the same question however, the complexity level of the two are vastly different.

What determines how quickly a car can stop? How do tires and brakes affect braking distance? This video explains an equation that can be used to determine how well a car brakes.

Want to include factors such as rain or ABS no ABS? Here is how to alter the equation. In the original equation, multiply u (frictional coefficient) by acceleration, so the new equation reads:
D=0.5*V^2/(u*a)
Leave a as 1, and change u according to the condition.
With ABS ON: u can be considered 1, since ABS will attempt to maintain peak friction.
With ABS OFF: u will be less than 1, and will equal the frictional coefficient of a tire slipping on pavement.
With RAIN, and ABS ON: u will be less than 1, and will equal the frictional coefficient of a tire on wet pavement.
With RAIN, and ABS OFF: u will be less than 1 (and than with ABS ON), and will be equal to the frictional coefficient of a tire slipping on wet pavement. This is the worst case scenario of the four listed.

[playitagainjohn]

I think your last calculation is incorrect. Shouldn’t you also divide the -15 by 2 per the quadratic equation which would give the answer as 21.76.

[HaroldWalden]

pretty standard exam question, I would probably make sure you know how to do this one if I were you :)

[kusshhal]

can anyone answer this question pls

A car is travelling at 40.0 m s−1. The driver sees
an emergency ahead and 0.50 s later slams on the
brakes. The deceleration of the car is 4.0 m s−2.
a Find the distance travelled before the car stops.
b Calculate the stopping distance if the driver
could apply the brakes instantaneously
without a reaction time.
c Calculate the di erence in your answers to a
and b.
d Assume now that the car was travelling at
30.0 m s−1 instead. Without performing any
calculations, state whether the answer to c
would now be less than, equal to or larger
than before. Explain your answer

[johnkupa]

part a. when u say, ''no he will not stop in time'' meaning he will hit the block. Is that what you meant?

[PaulAnthony]

I'm not a scholar by any stretch, but wouldn't the weight of the car make a difference in a real life scenario?

[seetheworld]

we can get the answere for 2question by doing the same thingto vxv=uxu plus 2as and we have to put s=40and find uxu and find u

[KR-uuqo]

Why isn’t the braking distance just S2?

[boboganbobogan]

can we also solve for part b if we take distance for the second part, s2, and make it equal to v nitial squared/20? Thanks for help

[makeasmartguess]

The calculation for a is right but the conclusion is yes he Wii hit the barrier

[paulsmith]

1. Stopping distance = thinking distance and breaking distance

[evajayme]

Hello Sir What is 3.6 ? where do you get that? Thank you..

[deanbrandt]

I don’t fucking understand it. I feel stupid. Been revising for ages and I just don’t get it. 😞

[meonjeo]

Can anyone solve this ?
Find the stoping distance if Vehicles weight = 300kg
Speed 40km/hr
Coefficient of friction of ground =0.8
Wheel dia= 566mm
Width =177mm
Consider all wheels locked.