Question

You are driving on a straight road at exactly 36.0 miles per hour when you see a child run out in front of your car, chasing a ball. You push the brakes hard, which results in an acceleration of exactly -36000 miles/hour2. The child freezes in panic and you cannot swerve to avoid the child because there are cars parked on both sides of the street. How many feet does your car travel before it comes to a complete stop? Your answer should be accurate to the nearest foot. (If you use equation 2.11 from the text to find the distance (X - Xo) in miles, you can use the fact that 1 mile = 5280 feet to find the distance in feet.) Note: "Reaction Time" is the time it takes for a person to perceive something and respond to it. In this problem, your reaction time is the time it takes to see the child, realize you need to stop, move your foot to the brake pedal and push it. Although reaction time can have a profound effect on your driving and safety, it is too complex to model here. In this problem we will make a simplifying approximation that the reaction time is zero. So you should ignore reaction time in this calculation and consider only the motion and acceleration of the car.

Answer 1