Question

A steel ball of radius 1 mm is falling vertically through a tank of oil at 30°C.

1. After some time the ball attains a constant velocity called_____

2. What are the forces acting on the ball and give their directions?

3. Write down the expression for resultant force acting on the ball?)

4. If the density of oil is 2 × 10³kg/m³, density of steel is 8 × 10² Kg/m³ and ‘η’of oil 2NS/m², What will be the constant velocity attained by the ball?

Answer 1

1. Terminal velocity.

2. Weight of body (down ward), bouyanant force (up ward), Viscous force (upward).

3. Resultant force = weight of body – buoyant force.

4. Terminal velocity,