physics homework help

Question

The hour and minute hands of Big Ben in London are 2.74 m and 4.45 m long and have masses of 57 kg and 103 kg respectively.

a) Calculate the total angular momentum of the minute hand about the center point. Treat the hand as long, thin rod. Treat “into the clock” as the positive direction. Answer in units of kg · m2 /s.

b) Calculate the total angular momentum of the hour hand about the center point. Treat the hand as long, thin rod, and “into the clock” as the positive direction. Answer in units of kg · m2 /s.

Answer 1

Angular momentum is written as Iω where I is the moment of inertia and ω is the angular velocity. The moment of inertia for a rod of mass M and length L rotating about it's end is ML²/3. Angular velocity for circular motion can also be written as 2π/T where T is the time to complete a full rotation. This should be enough to answer the question.