The term moment of momentum is called

Options

A. torque
B. impulse
C. couple
D. angular momentum

Answer

To solve the question regarding the term "moment of momentum," we will follow these steps:

### Step 1: Understand the Concept of Moment
The term "moment" in physics typically refers to a measure of the tendency of a force or quantity to cause rotation about a point or axis. For example, the moment of force is known as torque, which is calculated as the cross product of the position vector (r) and the force vector (F).

**Hint:** Recall that the moment of a quantity is generally defined as the vector product of the position vector and that quantity.

### Step 2: Define Linear Momentum
Linear momentum (p) is defined as the product of an object's mass (m) and its velocity (v). Mathematically, it is expressed as:
\[ p = m \cdot v \]

**Hint:** Remember that momentum is a vector quantity and has both magnitude and direction.

### Step 3: Relate Moment of Momentum to Angular Momentum
The moment of momentum refers to the angular momentum (L) of an object. Angular momentum is defined as the cross product of the position vector (r) and the linear momentum (p):
\[ L = r \times p \]

Substituting the expression for linear momentum, we get:
\[ L = r \times (m \cdot v) \]

**Hint:** Think about how angular momentum is related to both the position and the linear momentum of an object.

### Step 4: Express Angular Momentum in Terms of r, m, and v
Using the relationship established, we can express angular momentum as:
\[ L = r \times (m \cdot v) = m \cdot (r \times v) \]
This shows that angular momentum is dependent on both the mass of the object and its velocity, as well as the position vector.

**Hint:** Consider the geometric interpretation of the cross product in this context.

### Step 5: Conclude the Definition of Moment of Momentum
From the above derivation, we can conclude that the term "moment of momentum" is indeed equivalent to angular momentum. Therefore, we can state:
\[ \text{Moment of momentum} = \text{Angular momentum} \]

**Hint:** Look for definitions in your textbooks that confirm this relationship.

### Final Answer
The term "moment of momentum" is called **angular momentum**.