A rare species of insect about 1.5mm in diameter floats fully submerged just beneath the surface of the water in lakes and ponds. When threatened, it responds to danger by exuding a noxious substance from its tail that changes the surface tension on the skin of its tail. As a result the insect accelerates, shooting quickly across the water. Explain in detail why this occurs, and estimate the maximum velocity such an insect would be likely to achieve, and which direction the bug accelerates. The surface tension of water is 0.072 N m–1 and the viscosity is 10–3 Pa s. Don't solve it or anything yet. I'll post my attempt at an answer at a later time. Just needed to post the question now.