physics
posted by Laura .
A truck is stopped at a stoplight. When the light turns green, the truck accelerates at 2.5 m/s squared. At the same instant, a car passes the truck going 15 m/s. Where and when does the truck catch up with the car?

truck distance = (1/2)2.5 t^2
car distance = 15 t
so
15 t = 1.25 t^2
1.25 t^2  15 t = 0
t (1.25 t  15) = 0
t = 0 of course or t = 15/1.25 = 12 seconds
distance = 15 * 12 = 180 meters