Thinking with compound quantities

Wrong Track: You can just look at the speedo.

Wrong Track: Power is all around: you can see it in action.

Right Lines: Make the measurements, then combine your results to get the quantity where appropriate

Combine measures to calculate some quantities

Two or more separate measurements are often combined to work out a quantity. Take care to ensure this is clear. It's best not to cut corners, without sharing that you're doing that cutting.