Acceleration of a Block with Friction – Rankers Physics

Friction: Practice Problem & Solution

A block of mass \(20\text{ kg}\) is placed on a rough horizontal surface, and it is acted upon by a horizontal force of \(40\text{ N}\). If the coefficient of friction is \(0.2\), then the acceleration of the block is
\(2\text{ m/s}^2\)
\(3\text{ m/s}^2\)
Zero
\(1\text{ m/s}^2\)

Solution Explained:

To solve this problem, we apply the core principles of Friction. Understanding the underlying formula is key to arriving at the correct answer below:

The maximum limiting frictional force is \(f_{max} = \mu m g = 0.2 \times 20 \times 10 = 40\text{ N}\) (using \(g = 10\text{ m/s}^2\)). Since the applied force of \(40\text{ N}\) is equal to the limiting friction, the net horizontal force on the block is zero, resulting in zero acceleration.

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