Answer
(a)
1. An object lying on a table.
2. A balance.
3. A system where the resulting torque is zero.
(b)
1. A river where the quantity of water that enters it is equal to the volume of the liquid that leaves it.
2. Carbon dioxide molecules in a closed soda recipient.
3. The cells on the skin of a human body.
Work Step by Step
(a)
The sum of all the forces and torques is equal to zero, and the system is static, there is no change at all.
(b)
The things are moving, being removed and added, but the net change is equal to zero.
