Question

A block of mass M on an inclined surface is attached to a spring of negligible mass, as shown. The other end of the spring is attached to a wall, and there is negligible friction between the block and the incline. The block is pulled to a position such that the spring is stretched from its equilibrium position. The block is then released from rest. Which of the following systems can be classified as a closed system?

Answer 1

Closed system is block plus spring plus wall.

Explanation:

1. Closed system is imaginary boundary through which no force interact. Or we say that closed system is system on which net force is zero.

2. Now consider block

   There are force act by spring on block.

3. Now consider spring

  There are two force at end of spring. On one end of spring force is act by block. While on second end of spring force is act by wall.

4. Now consider wall

  There are force act by spring on wall.

5. For closed system, there should be zero force on system.

  So we have take block, spring and wall as a closed system.