Question

At the instant the traffic light turns green, a car that has been waiting at an intersection starts with a constant acceleration of 6 feet per second per second. At the same instant, a truck traveling with a constant velocity of 30 feet per second passes the car.
(a) How far beyond its starting point will the car pass the truck?
(b) How fast will the car be traveling when it passes the truck?

Answer 1

Answer:

(a) 300 ft

(b) 60 ft/s

Explanation:

distance $d=0.5at^{2}$ where a is acceleration and t is time

$d=0.5\times 6\times t^{2}=3t^{2}$

Also, d=vt where v is the velocity

d=30t

Therefore

$30t=3t^{2}$ hence t=10 s

Substituting t is either formula

d=30t=30*10=300 ft

Also

v=at hence $v=6\times 10=60 ft/s$