Mechanics: 1-Dimensional Kinematics

1-Dimensional Kinematics: Audio Guided Solution

Extra Problem 13:

A green car is following a yellow car down an expressway at a constant speed of 77.8 mi/hr. The separation distance between the two cars is 38.7 ft. The yellow car slams on the brakes and decelerates at a rate of -8.85 m/s/s. After a reaction of time of .381 seconds, the green car begins decelerating at a rate of -8.69 m/s/s. What is the final separation distance (in m) between the cars once stopped? If needed, the green car can change lanes and pass the yellow car. (Given: 1 m/s = 2.24 mi/hr; 3.28 ft = 1 m)

Audio Guided Solution

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Habits of an Effective Problem Solver

An effective problem solver by habit approaches a physics problem in a manner that reflects a collection of disciplined habits. An effective problem-solver...

• ...reads the problem carefully and develops a mental picture of the physical situation. If needed, they sketch a simple diagram of the physical situation to help visualize it.
• ...identifies the known and unknown quantities in an organized manner, often times recording them on the diagram iteself. They equate given values to the symbols used to represent the corresponding quantity (e.g., vo = 0 m/s; a = 4.2 m/s/s; vf = 22.9 m/s; d = ???.).
• ...plots a strategy for solving for the unknown quantity; the strategy will typically center around the use of physics equations be heavily dependent upon an understaning of physics principles.
• ...identifies the appropriate formula(s) to use, often times writing them down. Where needed, they perform the needed conversion of quantities into the proper unit.
• ...performs substitutions and algebraic manipulations in order to solve for the unknown quantity.