Question

If you run a movie film backward, it is as if the direction of time were reversed. In the time-reversed movie, would you see processes that violate conservation of energy? Conservation of linear momentum? Would you see processes that violate the second law of thermodynamics? In each case, if law-breaking processes could occur, give some examples.

Short answer

A simple example is a box is being slide on the floor and stopped by the friction. In the real-life direction of time kinetic energy is converted entirely into thermal energy. When time is reversed the box moves with increasing speed as thermal energy is converted to kinetic energy. This violates the second law of thermodynamics.

Step-by-step solution

Step 1:Conservation of energy and momentum

You would not see any process that violates conservation of energy or conservation of momentum.

These laws would be applied if the time is reversed because it is impossible that any process violates the conservation of energy and linear momentum.

Example of irreversible process

When an irreversible process in which the entropy of an isolated system increases will violate the second law of thermodynamics if it is run in reverse.

A simple example is a box is being slide on the floor and stopped by the friction. In the real-life direction of time kinetic energy is converted entirely into thermal energy. When time is reversed the box moves with increasing speed as thermal energy is converted to kinetic energy. This violates the second law of thermodynamics.