A particle moves in a straight line with a constant velocity. What is its angula
Practice Questions
Q1
A particle moves in a straight line with a constant velocity. What is its angular momentum about a point not on the line of motion?
Zero
Constant
Varies with time
Depends on distance
Questions & Step-by-Step Solutions
A particle moves in a straight line with a constant velocity. What is its angular momentum about a point not on the line of motion?
Step 1: Understand that angular momentum depends on the position of the particle and its velocity.
Step 2: Identify the formula for angular momentum (L) about a point: L = r × p, where r is the position vector from the point to the particle, and p is the linear momentum of the particle.
Step 3: Recognize that since the particle is moving with constant velocity, its linear momentum (p) is also constant.
Step 4: Note that the position vector (r) changes as the particle moves, but the direction of motion remains the same.
Step 5: Calculate the angular momentum at any point in time using the constant values of p and the changing r.
Step 6: Conclude that even though r changes, the angular momentum remains constant because the particle's velocity and the way it moves relative to the point do not change.
Angular Momentum – Angular momentum is the product of the particle's linear momentum and the perpendicular distance from the point of rotation to the line of motion.
Constant Velocity – A particle moving with constant velocity means its speed and direction do not change over time.
Point of Reference – The point about which angular momentum is calculated can affect the value of angular momentum, especially if it is not on the line of motion.