Chapter 8, Problem 1ASA

To determine

The meaning of stating that a quantity such as linear momentum is conserved.

Answer to Problem 1ASA

When a quantity is said to be conserved in a process, it means that the quantity has the same (magnitude and direction) both before and after the process. If a collision process is considered, the linear momentum of the total system before collision will be equal to that after collision, and hence linear momentum is conserved in the collision process.

Explanation of Solution

Conservation of physical quantities are very important in physics. There are many conservation laws such as conservation of linear momentum, conservation of angular momentum, conservation of total energy etc. The conservation of a quantity is always mentioned associated with a physical process. If the value of the quantity ( if it is vector, magnitude and direction, and if it is scalar, magnitude only) is unchanged in the process, then it is said to be conserved. The value of the quantity before process will be equal to the value after process.

The linear momentum conservation is one of the major conservation laws in physics. If collision process is considered, the linear momentum of the system before collision will be equal to that after collision.