Question

The given figure shows two masses at rest. The string is massless and the pulley is frictionless. The spring scale reads in kg. What is the reading of the scale?

Short answer

The reading of the spring scale is $5\mathrm{kg}.$

Step-by-step solution

Given information

The given figure shows two masses of $5\mathrm{kg}$at rest. The string is massless and the pulley is frictionless.

Explanation

According to the third law of motion "Every action has an equal and opposite reaction".

Therefore the masses attached at the ends of the string will exert equal forces on the string.

Since the pulley is frictionless, and the string is massless, the tension will remain constant throughout the string.

The tension in the string is equal to weight of $5\mathrm{kg},$hence the reading of the spring scale will be $5\mathrm{kg}$because it will read the tension in the string.

 Step 3 : Final answer

The spring scale reading is$5\mathrm{kg}.$