# Homework Help: Acceleration problem

1. Feb 1, 2009

### estie

1. The problem statement, all variables and given/known data
The maximum deceleration of a car on a dry road is about 8.0 m/s^2.
a. If two cars are moving head-on toward each other at 55 mi/h, and their drivers apply their brakes when they are 85m apart, will they collide?
On the same graph, plot distance versus time for both cars.
Assume x = 0 is the midpoint between the cars and t = 0 when the brakes are applied. Label the position versus time plot of the car with the positive velocity as x_1(t).

2. Relevant equations

3. The attempt at a solution
a. no they will not collide, they will be 10 m apart when they stop.
b. i think...
(0,-42.5) and (3,-5) for x_1(t)
and (0,42.5) and (3,5) for x_2(t)

2. Feb 1, 2009

### Delphi51

I get a little more than 10 - closer to 11 m apart.

3. Feb 1, 2009

### estie

how would part b be solved?

4. Feb 1, 2009

### Delphi51

Use the same d = formula to find the distance at a series of times and plot them on a graph.