Conceptual Example 14 provides useful background for this problem. A playground

Question

Conceptual Example 14 provides useful background for this problem. A playground carousel is free to rotate about its center on frictionless bearings, and air resistance is negligible. The carousel itself (without riders) has a moment of inertia of 125 kg · m2. When one PERSON is standing on the carousel at a distance of 1.5 m from the center, the carousel has an angular velocity of 0.6 rad/s. However, as this person moves inward to a point located 0.979 m from the center, the angular velocity increases to 0.8 rad/s. What is the PERSON'S mass?

Explanation / Answer

I(tot) = I + mr^2

-----Conservation of angular momentum------
I1w1 = I2w2

I1 = 125 + m(1.5)^2
w1 = 0.6 rad/s
I2 = 125 + m(0.979)^2
w2 = 0.8 rad/s

I1w1 = I2w2
(125 + m(1.5)^2)(0.6) = (125 + m(0.979)^2)(0.8)
m(0.6(1.5^2) - 0.8(0.979^2)) = 125(0.8 - 0.6)

m = 42.8634 kg

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.