Question

A block of mass 1 kg is attached to a horizontal spring and rests on a horizontal surface with a coefficient of friction 0.4. If the body is displaced by 1 cm by the tension in the spring, then the work done by the frictional force is:

• A. 0.04 J
• B. 1.14 J
• C. 2.00 J
• D. 0.02 J

Hint:

The work done by the frictional force can be calculated as \( W = F_{\text{friction}} \cdot d \), where \( F_{\text{friction}} = \mu \cdot N \) and \( N \) is the normal force.

Answer 1

The Correct Option is A

The normal force \( N \) on the block is equal to its weight: \[ N = m \cdot g = 1 \cdot 10 = 10 \, \text{N} \] The frictional force is: \[ F_{\text{friction}} = \mu \cdot N = 0.4 \cdot 10 = 4 \, \text{N} \] The work done by the frictional force is: \[ W = F_{\text{friction}} \cdot d = 4 \cdot 0.01 = 0.04 \, \text{J} \]
Hence, the work done by the frictional force is 0.04 J.