Two cars are travelling with the same speed and the drivers hit the brakes at the same time. The deceleration of one car is a quarter that of the other. By what factor do the distances required for two cars to come to a stop differ?

Respuesta :

Answer:

The ratio of stopping distances is 4 i.e by a factor 4 the stopping distances differ

Explanation:

Using 3rd equation of motion we have

For car 1

[tex]v_{1}^{^{2}}=u_{1}^{2}+2a_{1}s_{1}[/tex]

For car 2 [tex]v_{2}^{^{2}}=u_{2}^{2}+2a_{2}s_{2}[/tex]

Since the initial speed of both the cars are equal and when the cars stop the final velocities of both the cars become zero thus the above equations reduce to

[tex]u^{2}=-2a_{1}s_{1}\\\\s_{1}=\frac{-u^{2}}{2a_{1}}[/tex].............(i)

Similarly for car 2 we have

[tex]s_{2}=\frac{-u^{2}}{2a_{2}}[/tex]..................(ii)\

Taking ratio of i and ii we get

[tex]\frac{s_{1}}{s_{2}}=\frac{a_{2}}{a_{1}}[/tex]

Let

[tex]\frac{a_{2}}{a_{1}}=4[/tex]

Thus

[tex]\frac{s_{1}}{s_{2}}=4[/tex]

The ratio of stopping distances is 4