Question

Let’s allow ourselves to be a little more optimistic with our bus passengers. Earlier in the movie Sandy has to make the bus jump a large gap in the roadway. She is moving at 60 mph and as an astute physicist, she knows she must get the bus moving at a minimum of 80 mph within a half mile if she is to make the jump. Assuming constant acceleration, when does the bus make the jump after it begins to accelerate? (1 mile = 1609.34 m)

Answer 1

25.71486 seconds

Step-by-step explanation:

t = Time taken

u = Initial velocity = 60 mph

v = Final velocity = 80 mph

s = Displacement = 0.5 mile

a = Acceleration

Converting to m/s

`60* (1609.34)/(3600)=26.8223\ m/s`

`80* (1609.34)/(3600)=35.7631\ m/s`

From equation of motion

`v^2-u^2=2as\\\Rightarrow a=(v^2-u^2)/(2s)\\\Rightarrow a=(35.7631^2-26.8223^2)/(2* (1609.34)/(2))\\\Rightarrow a=0.34769\ m/s^2`

`v=u+at\\\Rightarrow t=(v-u)/(a)\\\Rightarrow t=(35.7631-26.8223)/(0.34769)\\\Rightarrow t=25.71486\ s`

Time taken is 25.71486 seconds