Exams › JEE Main › Physics

A uniform chain of total length 2L hangs in equilibrium over a small, smooth pulley (the string is inextensible). End B is given a slight downward displacement, causing the chain to accelerate. Find the acceleration of end B when it has been displaced a distance x from the equilibrium position.

1. x/L g
2. 2x/L g
3. x/(2L) g
4. g

Correct answer: x/L g

Solution

Let linear mass density be lambda. Unbalanced weight = lambda*(2x)*g (the extra length 2x on the heavier side). Total mass = lambda*2L. So a = (lambda*2x*g)/(lambda*2L) = (x/L) g.

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 →