answersLogoWhite

0


Best Answer

Because kinetic energy KE ~ V^2 (varies as the square of the speed). So ke ~ v^2 and KE ~ V^2 and when V = 2v, doubled, we have KE/ke = (V/v)^2 = (2v/v)%2 = 4 so that KE = 4 ke. QED. The new kinetic energy is four times the old.

And, ta da, that means there is four times as much energy for the brakes to sap and reduce to zero kinetic energy, which means V = 0 is the end speed (stopped). So by the work function, which you should know by now, we have WE = FS where F is the braking force (friction) and S is the stopping distance. We assume the braking force remains the same for both speeds.

Then KE - WE = 0, meaning the kinetic energy is sapped by the work so there is none left. And we have KE = WE = FS; so S = WE/F = KE/F and the stopping distance varies as the kinetic energy. So when the speed is doubled and the kinetic energy is quadrupled, the stopping distance is quadrupled because there is now four times as much kinetic energy to expend in stopping. QED.

User Avatar

Wiki User

11y ago
This answer is:
User Avatar

Add your answer:

Earn +20 pts
Q: Why if the speed of a car is doubled its braking distance is much more than doubled?
Write your answer...
Submit
Still have questions?
magnify glass
imp
Continue Learning about Math & Arithmetic

How many times more distance does it take to stop when speed is doubled?

Assuming a constant, linear deceleration, it takes four times the distance to stop when you double your speed. Using the formula v2 = u2 + 2as where v is final speed u is initial speed a is acceleration s is distance We can rearrange the formula to solve for s giving: s = (v2 - u2)/2a If we are finding the distance to that it takes to stop, the final velocity will be 0. Therefore distance to stop is given by s = -u2/2a Now we will look at the distance it takes to stop when speed is doubled. This will make our initial speed 2u. s = -(2u)2/2a = -2u2/a Comparing the two, we can see that when initial speed is doubled, it takes four times the distance to stop. (While it may look strange in the formula to have a negative sign in a distance measurement, remember that the car is decelerating, giving a negative acceleration. This means that the overall expression for distance will be positive.)


What is more faster km or hr?

Neither. These units measure distance and time, not speed.


What is an equation that relates two or more quantities?

A mathematical formula, such as Speed = Distance / Time for example.


What is the Average speed of 97.7 km?

97.7 kilometres (km) is a measure of distance. It makes no sense to try to convert that into a measure of speed: the distance could be traversed by electromagnetic radiation (light, for example) in less than a third of a millisecond, or more than a year for a slow snail.


What is formula of speed?

The definition of speed: speed = distance / time. You can also write this as distance = speed x time. This is used to do various calculations related to speed. The above is actually only valid for a constant speed. If the speed changes over time, speed - or more precisely velocity - is defined (using derivatives) as v = ds/dt. However, you need to have basic notions of calculus to work with this.

Related questions

Double your speed double stopping distance?

When your speed is doubled, your braking distance is multiplied by four.


Braking distance changes with the weather?

in rain, snow or ice your tires have much less traction, and therefore need more braking distance.


How many times more distance does it take to stop when speed is doubled?

Assuming a constant, linear deceleration, it takes four times the distance to stop when you double your speed. Using the formula v2 = u2 + 2as where v is final speed u is initial speed a is acceleration s is distance We can rearrange the formula to solve for s giving: s = (v2 - u2)/2a If we are finding the distance to that it takes to stop, the final velocity will be 0. Therefore distance to stop is given by s = -u2/2a Now we will look at the distance it takes to stop when speed is doubled. This will make our initial speed 2u. s = -(2u)2/2a = -2u2/a Comparing the two, we can see that when initial speed is doubled, it takes four times the distance to stop. (While it may look strange in the formula to have a negative sign in a distance measurement, remember that the car is decelerating, giving a negative acceleration. This means that the overall expression for distance will be positive.)


Does speeding have an effect on braking distance?

Yes, the faster you are moving the longer it will take to stop.


When training to drive a truck, do you have to do high speed braking from 100 mph or more?

Most trucking companies do not require you to do high speed braking for speeds of the extent. Normally when you are driving a truck, your speed shouldn't exceed 70 MPH due to speed limits. They will teach you high speed braking though to prepare you for a worse case scenario.


What is braking distance composed of?

Braking distance is usually measured by how fast you can stop at 60mph, 60-0, the make of a car is the factor of the stopping distance, each car varies. Your car can have disc brakes or drum brakes or both. Disc brakes are more effective than drum brakes. But braking distance is usually showed by how many feet it takes to stop from 60mph


What factor besides speed is important when calculating braking distance?

driving safely Things that affect braking distance consist of the following factors: * speed at which you're travelling * weight of the car * road conditions * braking efficiency * friction between the road surface and your tires What factors affect the thinking distance:


What change took place in the United Nations between 1945 and 1965?

Apex- It more than doubled in size.


What is a speed?

Basically "speed" tells you how fast something moves. It is defined as a distance divided by a time (more precisely, in the case of variable speed, the derivative of distance with respect to time).


What is the relationship between time and speed?

There is no relation between speed and time. if you add up the distance than the speed or time can be measured according to the distance measured. for example we say car A traveled 5 km in 20 minutes with a speed of 15 km/hour


How does distance and time affect speed?

Speed affects distance and time. The faster you go, relative to a stationary object, the more your time slows down and distance shrinks according to the stationary observer. However, you would notice nothing unusual time would progress normally and your distance would be the same according to you. According to you, you would see the stationary observer grow in distance and see there time speed up.


A car travels twice as fast as a second car. The faster car will take how much more distance to stop?

The stopping distance is not straightforward and depends on two factors: The time for a driver to react to a situation called the "thinking distance". The distance travelled in between the driver realising he needs to brake and actually braking and during which the car carries on moving. The distance taken to stop once the brakes are applied called the "braking distance". Both these factors combine to make the total stopping distance, which is not a linear scale. Thus going twice as fast does not simply double the distance. Thus without knowing what the speed of the slowest car is we can not tell you "how much more distance to stop" at 20 mph the distance is 40 feet (under ideal conditions). at 30, 75 feet at 40, 118 feet at 50, 175 feet at 60, 240 feet at 70, 315 feet