A circular metal plate of radius 4 cm rests on a layer of castor oil 2 mm thick, whose coefficient of viscosity is 16.5 `Nsm^(-2).` Calculate the horizontal force required to move the plate with a speed of 3 cm/s.

Explanation

To solve the problem of calculating the horizontal force required to move a circular metal plate on a layer of castor oil, we will follow these steps:

### Step 1: Identify the given values
- Radius of the circular plate, \( r = 4 \, \text{cm} = 0.04 \, \text{m} \)
- Thickness of the castor oil layer, \( dy = 2 \, \text{mm} = 0.002 \, \text{m} \)
- Coefficient of viscosity of castor oil, \( \mu = 16.5 \, \text{N s/m}^2 \)
- Speed of the plate, \( v = 3 \, \text{cm/s} = 0.03 \, \text{m/s} \)

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