Question

Find deacceleration An engineer in a locomotive sees a car stuck on the track at a railroad crossing in front of the train. When the engineer first sees the car, the locomotive is 360 m from the crossing and its speed is 16 m/s. If the engineer’s reaction time is 0.53 s, what should be the magnitude of the minimum deceleration to avoid an accident? Answer in units of m/s^2

Answer 1

Answer:

The deceleration is  $a = -0.7273 \ m/s^2$  

Explanation:

From the question we are told that

  The distance of the car from the crossing is $d = 360 \ m$

   The speed is $u = 16 \ m/s$

    The reaction time of the engineer is  $t = 0.53 \ s$

Generally the distance covered during the reaction time is  

      $d_r = u * t$

=>   $d_r = 16 * 0.53$

=>   $d_r = 8.48 \ m$

Generally distance of the car from the crossing after the  engineer reacts is

      $D = d- d_r$        

=> $D = 360 - 8.48$      

=> $D = 352 \ m$

Generally from kinematic equation

      $v^2 = u^2 + 2as$

Here v is the final velocity of the car which is  0 m/s

So

        $0^2 = 16^2 + 2 * a * 352$

=>    $a = -0.7273 \ m/s^2$