Posted by billy on Saturday, November 6, 2010 at 7:38pm.
If two cars are traveling along a straight road, one behind the other. the first is traveling at a constant velocity of 10 m/s. the second, approaching from the rear, is traveling at 22 m/s. when the second car is 300m behind the first, the driver applies the brakes, producing a constant acceleration of 0.40 m/s^2. will the cars crash and if so, where and when?
I find this really hard to understand

phyics  hy, Sunday, November 7, 2010 at 12:30am
will it hit?
use final velocity of 0 presuming that it came to a halt
find the time elasped for it to stop using acceleration = change in v over change in t
use the time to find how far both have traveled...
yes it will hit
it;s an equation of what time used for second car to travel 300+11t
since we don't know the final velocity cant use equations of it
so use change in x = intial v (t) + 1/2 a t^2
so 300+11t=22t+(2)t^2
2t^211t+300=0
using solve t using quadratic formula to see what time will it hit