A construction crane raises a 500 kg platform 6.0 m in 12 seconds at constant speed, and the animation walks through finding work done (mgh), average power (W/t), and a cross-check using P = Fv. A second worked example with an elevator car of 400 kg reinforces the same three-step method. Useful for physics students learning to connect work, power, force, and velocity through consistent unit tracking and verification.
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Scene 6: Solved Examples (Problems 1 & 2)Problem 1 (Solved Main Example - Construction Crane):Prompt & Motion: A construction crane lifting a platform of mass 500 kg vertically to a height of 6.0 m at a constant speed in 12 seconds ($g = 9.8\text{ m/s}^2$). Voiceover & Step-by-Step Breakdown:Given: $m = 500\text{ kg}$, $h = 6.0\text{ m}$, $t = 12\text{ s}$, $g = 9.8\text{ m/s}^2$. (A) Work Done ($W$):Calculation: $W = m \cdot g \cdot h = 500 \times 9.8 \times 6.0 = \mathbf{29,400\text{ J}}$ (or $2.94 \times 10^4\text{ J}$). (B) Average Power ($P$):Calculation: $P = W / t = 29,400 / 12 = \mathbf{2,450\text{ W}}$ (or $2.45\text{ kW}$). (C) Check using $P = F \cdot v$:Speed: $v = h / t = 6.0 / 12 = 0.5\text{ m/s}$. Power: $P = (m \cdot g) \cdot v = 500 \times 9.8 \times 0.5 = \mathbf{2,450\text{ W}}$ ($2.45\text{ kW}$). Problem 2 (Try It Yourself - Elevator Car):Prompt & Motion: An elevator car of mass 400 kg rising vertically to a height of 9.0 m at constant speed in 15 seconds ($g = 9.8\text{ m/s}^2$). Voiceover & Step-by-Step Breakdown:Given: $m = 400\text{ kg}$, $h = 9.0\text{ m}$, $t = 15\text{ s}$, $g = 9.8\text{ m/s}^2$. Calculation 1 (Work): $W = 400 \times 9.8 \times 9.0 = 35,280\text{ J}$. Calculation 2 (Power): $P = 35,280 / 15 = \mathbf{2,352\text{ W}}$ ($2.35\text{ kW}$). Check ($P = Fv$): $v = 9.0 / 15 = 0.6\text{ m/s}$ $\rightarrow$ $P = (400 \times 9.8) \times 0.6 = \mathbf{2,352\text{ W}}$ ($2.35\text{ kW}$). IMPORTANT LANGUAGE RULE: All on-screen text must be in Arabic EXCEPT mathematical equations, formulas, laws, symbols, variables, and numerical expressions. Keep every equation, formula, and law exactly as provided, without translating or changing it. Translate only the explanatory text, headings, labels, and descriptions into Arabic. Arabic text must use proper RTL direction and correct Arabic typography. Do not use English text anywhere else on the screen. Audience: student