Exams › JEE Main › Physics

A light spring balance is suspended from the hook of another light spring balance, and a block of mass M kg is attached to the lower balance. Which statement correctly describes the readings shown by the balances?

1. Each balance shows a reading of M kg.
2. The lower balance shows M kg while the upper balance shows zero.
3. The two readings may vary, but their total will always be M kg.
4. Each balance shows a reading of M/2 kg.

Correct answer: Each balance shows a reading of M kg.

Solution

Both balances measure the weight of the block, which is the same for each balance since they are in a direct line of support. Therefore, each balance will show a reading equal to the mass of the block, M kg.

Related JEE Main Physics questions

• Which of the following has the same SI unit as impulse?
• A monkey slides downward from a tree branch with uniform acceleration. If the maximum tension the branch can withstand is 75% of the monkey’s weight, what is the least downward acceleration that will allow the monkey to descend without snapping the branch?
• A 1000 kg car is travelling at 30 m/s. The brakes are applied until it stops. If the friction force between the tyres and the road is 5000 N, how long will the car take to come to rest?
• A rocket initially ejects gas from its rear at a mass rate of 0.1 kg s⁻¹. If the exhaust speed relative to the rocket is 50 m s⁻¹ and the rocket’s mass is 2 kg, what is its acceleration in m s⁻²?
• A block of mass M rests on a rough level floor with coefficient of friction μ. A person applies a horizontal pull, but the block remains at rest. If the total contact force exerted by the floor on the block is F, then
• Which of the following types of motion on a frictionless plane surface occurs without any force acting on the body?

⚔️ Practice JEE Main Physics free + battle 1v1 →