A rotor has identical blades that exert equally spaced force impulses on the turbine…

PHYSICS · Single correct · A Level · Physics · Further mechanics and thermal physics · Further mechanics and thermal physics

Problem

A rotor has

5

identical blades that exert

5

equally spaced force impulses on the turbine casing every revolution. The natural frequency of the casing is

100\,\text{Hz}

. Which rotational speed of the rotor is most likely to produce resonance in the casing? (a)

1000\,\text{rpm}

(b)

1200\,\text{rpm}

(c)

1500\,\text{rpm}

(d)

3000\,\text{rpm}