Question 894874
A car traveling at 80 kilometers per hour is passed by a second car going in the same direction at a constant speed.
 After 30 seconds, the two cars are 500 meters apart.
 Find the speed of the second car.
:
let s = speed of the 2nd car in meters/sec
:
Change 80 km/hr to meters/sec: {{{(1000*80)/3600}}} = 22.22 meters/sec
then
(22.22-s) = the relative speed between the two cars
:
Write a distance equation, dist = time * speed
30(22.22-s) = 500
666.67 - 30s = 500
-30s = 500 - 666.67
-30s = -166.67
s = -166.67/-30
s = +5.56 meters/sec, speed of the second car
Change to km/h
{{{(3600*5.56)/1000}}} = 20 km/hr