SOLUTION: An auto A is moving at 30 fps and accelerating at 5 fps^2 to overtake an auto B which is 384 ft ahead. Auto B is moving at 60 fps and decelerating at 3 fps^2 (a) How soon will A

Algebra.Com
Question 1165401: An auto A is moving at 30 fps and accelerating at 5 fps^2 to overtake an auto B
which is 384 ft ahead. Auto B is moving at 60 fps and decelerating at 3 fps^2
(a) How soon will A pass B?
(b) What is the total distance traveled by car A?

Answer by Theo(13342)   (Show Source): You can put this solution on YOUR website!
i believe the distance formula for an accelerating car is y = ax + (b/2)x^2 and the distance formula for a decelerating car is y = ax - (b/2)x^2

x is the number of seconds.
y is the distance traveled in x seconds.
a is the constant velocity
b is the constant constant acceleration.

applying this to your situation gets you.

y = 30 * x + 5/2 * x^2 for the accelerating car.

y = 60 * x - 3/2 * x^2 for the decelerating car.

both cars will have traveled the same distance when 30 * x + 5/2 * x^2 = 60 * x - 3/2 * x^2

solve for x to get x = 7.5 seconds.

both cars will have traveled the same distance in 7.5 seconds, after w hich the accelerating car will have passed the decelerating car.

at this point in time, the distanced traveled by each car will be 365.625 feet.

the equations for each car can be graphed.
the intersection of the lines on the graph is when both cars will have traveled the same distance.

the equation for the accelerating car is y = 30x + 5/2 * x^2.
the equation for the decelerating cvar is y = 60x - 3/2 * x^2.

the graph confirms the solution expressed above (365.625 feet in 7.5 seconds for both cars).



i also used a calculator to confirm the formulas were correctly applied.

for the accelerating car .....




for the decelerating car .....




both the graph and the calculator confirm the calculations are correct.

this assumes, of course, that i'm using the right formula.
i'm reasonably confident that i am.






RELATED QUESTIONS

if a car is moving at 35 mph is it moving 50... (answered by Alan3354)
An auto, moving too fast on a horizontal stretch of moutnain road, slides off the road,... (answered by ikleyn)
A train is moving along a straight stretch of track parallel to a highway. An automobile (answered by Theo)
An automobile makes a trip of 270 miles in 2 1/2 hours less than it takes the same auto... (answered by jorel1380)
An auto travels at the rate of 35-km/h, N for 6.0mins, then NE for 7.0mins and finally at (answered by KMST)
How long does it take for a auto traveling at 64mph to travel 30... (answered by ankor@dixie-net.com)
To deliver a message, an army officer will travel by auto at 75 miles per hour from A to... (answered by MathTherapy,macston,josmiceli)
CNNBC recently reported that the mean annual cost of auto insurance is 1046 dollars.... (answered by Boreal)
The population of Cartown, USA has decreased by 1/4 over the last year due to an auto... (answered by checkley77)