Question

2) On top of a baby's crib there is a sun and moon mobile. The motor provides a 0.03 N-cm torque about the j-axis and has a terminal angular velocity of 35 RPM (rotations per minute). The moon and the sun both have a mass of 25 grams. The position vector of the moon is rn25 i-5 j] cm and the sun is rs I-25 -5 j] cm. Be very careful with your units in this problem! Be sure to write them through! Calculate how long it takes the motor to reach its terminal angular velocity. Hint: think carefully about how to find the velocity of the moon and the sun and which direction that velocity would be for each. [Ans. to check: 38.18 s a. b. s there a moment about k? If no, what would have to change so there could be a moment about k?

FBD
Use Sum M = r x mv - r x mv (final momentum - initial momentum) and polar coordinates: e sub theta, e sub r, and k directions

Answer 1

25 Terminal Angular Yelo(ify 5 Am : 60 0103

f hange the plane of both Soo rmoun on any one of tham thu Pexfeodiolar distanG bedulen Centrifusal ores cilu be a finite alu and that era 2 of