A small steel sphere is dropped into a tall column of viscous silicone oil. After a short time, the sphere is observed to descend at a constant speed.
State the physical term used to describe this constant speed.
Explain, in terms of the forces acting on the sphere, why it reaches and maintains this constant speed.
56 exam-style questions on Edexcel IGCSE Physics Forces, movement, shape and momentum. Each one has a worked solution and a mark scheme showing where the marks go.