In the movie speed, a bus already moving faster than 55 mph will explode if the bus’ speed falls below 55 mph. let say that the bus is already moving at 80 mph when sandra bullock (the bus driver) passes out and her foot falls off the accelerator. 30.0 seconds later, the bus explodes. how far did the bus move after our girl sandy passed out? answer in meters!

The bus moved after our girl Sandy passed out = S = 905.04 m

Explanation:

At  t = 0 sec              Vi = 80mph = 35.76 m/s

    t = 30 sec             Vf = 55mph = 24.58 m/s

According to the first equation of motion

                   Vf = Vi + at

        24.587 = 35.76 + a(30)

        a  =  - 0.373 m/s2 (negative sign shows deceleration)

 Now for distance travelled in 30 sec we have

second equation of motion

                 S=Vit+1/2at2

        S = 35.76 x 30 + 1/2 x -0.373 x 30 x 30

         S = 905.04 m

conservation of mass

mass before something happens = mass afterwards