Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

What is defined as the rate at which work is completed?

1. Efficiency

2. Power

3. Force

4. Velocity

The correct answer is: Power

The rate at which work is completed is defined as power. In physics, power is quantified as the amount of work done per unit of time. It represents how quickly a certain amount of energy is transferred or converted. In mathematical terms, power can be expressed with the equation: \[ P = \frac{W}{t} \] where \( P \) is power, \( W \) is work done, and \( t \) is the time taken to do that work. This fundamental concept illustrates that even if a significant amount of work is achieved, the power will vary depending on how quickly the work is done. The other options represent different concepts: efficiency refers to the ratio of useful work output to total energy input, force is an interaction that causes an object to change its motion, and velocity describes the speed and direction of an object’s motion. These definitions help clarify that power specifically relates to the timing of work completion, distinguishing it from other scientific terms.