Question

A car is traveling at a speed of 30.0m/s encounters an emergency and comes to complete stop how much time will it take for the car to stop if it decelerates -4.O m/s^2

Answer 1

`7.5\ seconds`

Explanation:

The Equation of motion is given by

`v=u-at\\\\\ v:Final\ Velocity\\u:Initial\ Velocity\\a:acceleration\\t:time`

Here
`v=0(as\ at\ the\ end\ car\ stops), u=30m/s,a=-4m/s^2`

`0=30-4t\\\\4t=30\\\\t=(30)/(4)\\\\t=7.5\ seconds`