 Solution

ID: past-exam-of-the-mathematical-and-computational-biology-course-of-the-university-of-cambridge/2025/paper-2/7/a/solution

The substrate contact area is the square bottom face, so the total traction force magnitude is stress times area:

F = 100 N m^{- 2} (20 \times 1 0^{- 6} m)^{2} = 4.0 \times 1 0^{- 8} N = 40 nN .

By Newton's third law, the force exerted by the substrate on the biological cell has the same magnitude and opposite direction to the cell's force on the substrate.

 New to topics? Read the docs here!