Q1: The practical units of work, is

ANS:B - joule

The practical unit of work is the joule (J). Work is defined as the product of force and displacement in the direction of the force. In the International System of Units (SI), the unit of force is the newton (N), and the unit of displacement is the meter (m). Therefore, the unit of work is the newton-meter (N·m), which is equivalent to the joule. The other units mentioned, erg and dyne, are smaller units typically used in other systems of measurement, such as the CGS (centimeter-gram-second) system. The erg is a unit of energy and work in the CGS system, while the dyne is a unit of force. However, in practical applications and everyday usage, the joule is the standard unit of work used in the SI system.