Physics help, circular motion and gravity

AI Thread Summary
The discussion focuses on two physics problems involving circular motion and gravity. The first problem calculates the new rotation period of a star after its diameter shrinks, assuming uniform mass distribution. The second problem involves a pulley system with two masses, examining the relationships between tensions and gravitational forces. Participants emphasize the importance of adhering to forum rules for effective assistance. Overall, the thread highlights the complexities of gravitational interactions and rotational dynamics in physics.
katiegerster
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anything is appreciated!

1. The mass of a star is 1.830×1031 kg and it performs one rotation in 37.30 days. Find its new period (in days) if the diameter suddenly shrinks to 0.850 times its present size. Assume a uniform mass distribution before and after.

2. A pulley with mass Mp and a radius Rp is attached to the ceiling, in a gravity field of 9.81 m/s2 and rotates with no friction about its pivot. Mass M2 is larger than mass m1. The quantities Tn and g are magnitudes. Choices: true, false, greater than, less than, or equal to.

The C.M. of Mp+M1+M2 does not accelerate.
T1 is ... T2
m1g + M2g + Mpg is ... T3.
T3 is ... T1 + T2
T2 is ... M2g.
The magnitude of the acceleration of M2 is ... that of m1.
 
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This (and the other) post of yours violate the rules of this forum. You won't get any help unless you stick with the rules.
 
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