Question Detail

PHY 101 Rigid Body Dynamics Objective Question
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Question

In the derivation of τ = dL/dt, the term (dr/dt) × p becomes zero. Why is this term equal to zero?
Options
A Because dr/dt is always zero.
B Because dr/dt is perpendicular to p.
C Because dr/dt is parallel to p, and the cross product of parallel vectors is zero.
Correct Answer
D Because p is constant.
Correct Answer

Option C is the correct answer.

Detailed Explanation

The term (dr/dt) × p is v × p. Since linear momentum p = m v, this becomes v × (m v) = m (v × v). The cross product of any vector with itself is always zero because they are parallel (sin 0° = 0).

Hint

What is the geometric relationship between the velocity vector v and the momentum vector p?

Question Info

Course: PHY 101
Topic: Rigid Body Dynamics
Type: Objective
Difficulty: Not specified
Question 646 of 1250
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