SOLUTION: 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 instan

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Question 287734: 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 by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
The formula for the car is
d+=+%281%2F2%29%2Aat%5E2
where
d = distance traveled
a = acceleration from stop
t = elapsed time
The formula for the truck is
d+=+vt
v = the velocity
----------------------
given:
a+=+6 ft/sec/sec
v+=+30 ft/sec
---------------
d+=+%281%2F2%29%2A6t%5E2
and
d+=+30t
so,
%281%2F2%29%2A6t%5E2+=+30t
3t%5E2+=+30t
t+=+10
and
d+=+30t
d+=+30%2A10
d+=+300
(a) the car passes the truck 300 ft from start
and
For car v+=+a%2At
v+=+6%2A10
v+=+60
(b) the car's velocity is 60 ft/sec when it passes the truck