Physics 9702/22 — May/June 2013

Cambridge AS Level · AS Level Structured Questions · worked solutions for every part, with the mark scheme

questions

marks

minutes

Topics Physical Quantities and Units · Dynamics · Particle Physics · Work, Energy and Power · Forces, Density and Pressure · Waves · +2 more

Q1Physical Quantities and UnitsWork, Energy and PowerFree sample

(a)

Determine the SI base units of power.

SI base units of power = ______

(b)

Fig. 1.1 shows a turbine that is used to generate electrical power from the wind.

Fig. 1.1

The power $P$ available from the wind is given by

P = CL^2\rho v^3

where $L$ is the length of each blade of the turbine,
$\rho$ is the density of air,
$v$ is the wind speed,
$C$ is a constant.

(i)

Show that $C$ has no units.

(ii)

The length $L$ of each blade of the turbine is $25.0\ \text{m}$ and the density $\rho$ of air is $1.30$ in SI units. The constant $C$ is $0.931$ .
The efficiency of the turbine is $55\%$ and the electric power output $P$ is $3.50 \times 10^5\ \text{W}$ .

Calculate the wind speed.

wind speed = ______ $\text{m s}^{-1}$

(iii)

Suggest two reasons why the electrical power output of the turbine is less than the power available from the wind.

______
______

The rest of this paper

6 more questions

Q2Dynamics10M
Q3Forces, Density and Pressure · Physical Quantities and Units · Dynamics10M
Q4Particle Physics6M
Q5Waves · Superposition10M
Q6Electricity8M
Q7Particle Physics5M

Loading the full paper…