Question

A big size balloon of mass M is held stationary in air with the help of a small block of mass M/2 tied to it by light string such that both float in mid air. Describe the motion of the balloon and the block when the string is cut. Support your answer with calculations.

Answer 1

When the string is cut, the balloon will move upward due to the expulsion of air, while the block will move downward under the force of gravity.

Step-by-step explanation:

When the string holding the block and balloon together is cut, both objects will experience different types of motion.

The balloon, being larger and lighter than the block, will experience a upward motion due to the air inside the balloon being expelled downward as it goes out. This is a result of Newton's third law of motion that states for every action, there is an equal and opposite reaction. As the air inside the balloon is pushed out in one direction, the balloon experiences a propulsive force in the opposite direction.

The block, which is denser and heavier than the balloon, will experience a downward motion due to the force of gravity. Since the string is cut, there is no longer a force pulling the block upwards, so it will fall freely under the influence of gravity.