When it comes to measuring the "hardness" of a material, most tests are distinctly low-tech and basically involve pressing a diamond tip into the surface and measuring the size of the dent produced.

It is important to remember that the distance is the perpendicular distance from the pivot to the line of action of the force. A force of 15 N is applied to a door handle, 12 cm from the pivot.

To calculate the force on a wire carrying a current at right angles to a magnetic field, use the equation: force on a conductor carrying a current = magnetic field strength × current × length A 50 cm ...