A van traveling at a speed of 36.0 mi/h needs a minimum of 50.0 ft to stop. If the same van is traveling 69.0 mi/h, determine its minimum stopping distance (in ft), assuming the same rate of acceleration.

Respuesta :

Answer:

Van will stop after a distance of 183.216 ft

Explanation:

We have given initial speed of the van = 36 mi/hr

As the van finally stops so final velocity v = 0 mi/hr

Distance after which van stop = 50 ft

As 1 ft = 0.000189 mi

So 50 ft [tex]=50\times 0.000189=0.00945mi[/tex]

From third equation of motion [tex]v^2=u^2+2as[/tex]

[tex]0^2=36^2+2\times a\times 0.00945[/tex]

[tex]a=-68571.42mi/hr^2[/tex]

In second case u = 69 mi/hr

And acceleration is same

So [tex]0^2=69^2-2\times 68571.42\times s[/tex]

[tex]s=0.03471mi[/tex]

As 1 mi = 5280 ft

So [tex]0.0347mi=0.0347\times 5280=183.216ft[/tex]