IB Physics HL A 3 12 Power Questions

Practise HL power calculations for wind turbines, energy dissipation, momentum flow, efficiency and system assumptions in exam questions.

Exam points

Calculate power as the rate of work or energy transfer, P = ΔW/Δt.
Relate power to force and velocity using P = Fv and interpret energy, work, time or velocity data with complete evidence.

[Maximum number: 2]

The graph shows the variation with time of the height of the International Space Station (ISS) during a 30-day period.

Figure for Question IB Physics HL A 3 12 Power Questions question 1 — IB Physics HL

The following data are available:

\begin{aligned} \text { Mass of Earth } & =5.98 \times 10^{24} \mathrm{~kg} \\ \text { Mass of the ISS } & =4.20 \times 10^{5} \mathrm{~kg} \\ \text { Radius of the Earth } & =6.38 \times 10^{6} \mathrm{~m} \end{aligned}

For the 30-day period indicated in the graph the loss of total energy of the ISS is $4.5 \times 10^{9} \mathrm{~J}$ .

Calculate the average rate at which the energy of the ISS is being dissipated.

$\begin{aligned} P=\frac{\Delta E}{\Delta t} \quad P=\text { « } \frac{-4.5 \times 10^{9}}{30 \times 24 \times 3600} \text { » }-1.7 \times 10^{3} W \end{aligned}$

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IB Physics HL A 3 12 Power Questions question 1