The system shown in the figure is in equilibrium at rest and the spring and string are massless. Now the string is cut. The acceleration of masses 2m and m just after the string is cut will be:

By BYJU'S Exam Prep

Updated on: September 25th, 2023

The acceleration of masses 2m and m just after the string is cut will be g/2 upwards, g downwards

When the system is in equilibrium:

FBD of the system:

The system shown in the figure is in equilibrium at rest and the spring and string are massless. Now the string is cut. The acceleration of masses 2m and m just after the string is cut will be

applying the vertical equilibrium condition to the system

F_spring = 3mg

After the string is cut, T = 0 i.e tension in string becomes zero, while spring force acts at its initial value F_spring, because of inertia of spring.

FBD of the individual blocks following string cutting is shown here:

The system shown in the figure is in equilibrium at rest and the spring and string are massless. Now the string is cut. The acceleration of masses 2m and m just after the string is cut will be

Table of content

1. The system shown in the figure is in equilibrium at rest and the spring and string are massless. Now the string is cut. The acceleration of masses 2m and m just after the string is cut will be:

Acceleration of block of mass m is given by

a_m = mg/m

On simplifying we get

a_m = g (Downwards)

Acceleration of block of mass 2m is given by

a_2m = F_spring – 2mg/ 2m = mg/2m

On simplifying we get

a_2m = g/2 (upwards)

Features of Free Body Diagram

A diagram that changes when the issue is resolved is called a free-body diagram. A free body diagram often includes the following elements:

a condensed form of the body (most commonly a box)
a coordinate framework
Arrows showing in the direction in which forces act on the body are used to depict forces.
Moments appeared as curved arrows pointing towards the body’s acting direction.

The specific problem and the presumptions used will determine how many forces are acting on a body. Friction and air resistance are frequently ignored.

Summary:-