Question

On the interstate, the speed limit is 60 mi/h (about 100 km/h) a skilled driver can safely decelerate at about 6.1m/s^2. How long would it take to stop the vehicle? What would the total stopping distance be?

Answer 1

4.56 seconds

63.25 m

Step-by-step explanation:

t = Time taken for the car to stop

u = Initial velocity = 60 km/h = 100 km/h = 100000/3600 = 27.78 m/s

v = Final velocity = 0

s = Displacement

a = Acceleration = -6.1 m/s²

Time taken by the car to stop

`v=u+at\\\Rightarrow t=(v-u)/(a)\\\Rightarrow t=(0-27.78)/(-6.1)\\\Rightarrow t=4.56\ s`

Time taken by the car to stop is 4.56 seconds

`s=ut+(1)/(2)at^2\\\Rightarrow s=27.78* 4.56+(1)/(2)* -6.1* 4.56^2\\\Rightarrow s=63.25\ m`

The total stopping distance would be 63.25 m