Question Detail

PHY 101 Work, Energy and Power Objective Question
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Question

Under what condition is the work done by a force zero?
Options
A When the force and displacement are in the same direction (θ = 0°).
B When the force and displacement are in opposite directions (θ = 180°).
C When the force and displacement are perpendicular (θ = 90°).
Correct Answer
D Work can never be zero.
Correct Answer

Option C is the correct answer.

Detailed Explanation

Work is given by W = (F cos θ)Δx. If θ = 90°, cos 90° = 0, so the work done is zero. For example, carrying a bucket horizontally at constant speed: the force is vertical, displacement is horizontal.

Hint

A force does no work if it has no component along the displacement.

Question Info

Course: PHY 101
Topic: Work, Energy and Power
Type: Objective
Difficulty: Not specified
Question 383 of 1250
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