Instantaneous Power Calculation – Rankers Physics

Power: Practice Problem & Solution

A particle moves with a velocity \((5\hat{i} - 3\hat{j} + 6\hat{k}) \text{ms}^{-1}\) horizontally under the action of constant force \((10\hat{i} + 10\hat{j} + 20\hat{k}) \text{N}\). The instantaneous power supplied to the particle is :
100 W
140 W
200 W
Zero

Solution Explained:

To solve this problem, we apply the core principles of Power. Understanding the underlying formula is key to arriving at the correct answer below:

Instantaneous power is calculated using the dot product of force and velocity: \(P = \vec{F} \cdot \vec{v} = (10)(5) + (10)(-3) + (20)(6) = 50 - 30 + 120 = 140 \text{W}\).

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