Technical Mathematics, Sixth Edition

3.3. Uniform Motion Applications

Number puzzles were a good warm-up, but now we will do some problems having more application to technology.

Everything you need to solve these problems is given right here. However, with these and others throughout the text, you may search in vain for an example that exactly matches. That is what makes them difficult but also what makes them valuable. Instead of just plugging new numbers into an already worked example, you must dig a bit deeper and apply the basic ideas from the example to the new situation.

Do not be reluctant to try problems outside your chosen field. Some familiarity with other branches of technology will make you more valuable on the job.

We will start with uniform motion problems. The ideas here should be familiar; you already know that if you walk at a rate of 3 miles per hour for 2 hours you will travel 6 miles. The problems in this section are based on that one simple idea.

Motion is called uniform when the speed does not change. The distance traveled at constant speed is related to the speed (the rate of travel) and the elapsed time by

rate × time = distance

or

RT = D

Be careful not to use this formula for anything but uniform motion.

Also, when using this formula or any other, we must be careful with units of measure. The units must be consistent. Do not mix feet and miles, for example, or minutes and hours. You may have to convert units, as we did in Chap. 1, so that they cancel properly, and further, leave your answer ...