Q1: The rate of change of moment of momentum represents the __________ by the fluid.

ANS:A - torque applied

The rate of change of moment of momentum represents the force exerted by the fluid. Here's an explanation:

• Moment of Momentum: Moment of momentum (or angular momentum) in fluid mechanics is analogous to linear momentum but in rotational motion. It is defined as the cross product of position vector and linear momentum.
• Rate of Change of Moment of Momentum: This represents the torque (or moment of force) exerted by the fluid. Torque is the rate of change of angular momentum.
• Force Exerted: Torque (or moment of momentum) in fluid mechanics is directly related to the force exerted by the fluid on a body. When a fluid exerts a force on a body, it results in a torque that causes rotational motion or moment of momentum changes.