Question

Calculate the angular momentum of a body whose rotational energy is 10 joule. If the angular momentum vector coincides with the axis of rotation and its moment of inertia about this axis is 8×10–7 kg m2:

• A. 4×10–3 kg m2/s
• B. 2×10–3 kg m2/s
• C. 6×10–3 kg m2/s
• D. None of these

Answer 1

Answer: (A)

4×10–3 kg m2/s

Answer 2

$L = \sqrt{2EI} = \sqrt{2 \times 10 \times 8 \times 10^{- 7}} = 4 \times 10^{- 3}kg^{2}/s$