AQA
M3
2008
June
Q1
6 marks
Standard +0.3
1 The speed, \(v \mathrm {~m} \mathrm {~s} ^ { - 1 }\), of a wave travelling along the surface of a sea is believed to depend on
the depth of the sea, \(d \mathrm {~m}\),
the density of the water, \(\rho \mathrm { kg } \mathrm { m } ^ { - 3 }\),
the acceleration due to gravity, \(g\), and
a dimensionless constant, \(k\)
so that
$$v = k d ^ { \alpha } \rho ^ { \beta } g ^ { \gamma }$$
where \(\alpha , \beta\) and \(\gamma\) are constants.
By using dimensional analysis, show that \(\beta = 0\) and find the values of \(\alpha\) and \(\gamma\).
AQA
M3
2011
June
Q2
5 marks
Standard +0.3
2 The time, \(t\), for a single vibration of a piece of taut string is believed to depend on
the length of the taut string, \(l\),
the tension in the string, \(F\),
the mass per unit length of the string, \(q\), and
a dimensionless constant, \(k\),
such that
$$t = k l ^ { \alpha } F ^ { \beta } q ^ { \gamma }$$
where \(\alpha , \beta\) and \(\gamma\) are constants.
By using dimensional analysis, find the values of \(\alpha , \beta\) and \(\gamma\).