A ballet dancer spins with 2.4 rev/s with her arms outstretched, when the moment of inertia about axis of rotation is 1 .With her arms folded, the moment of inertia about the same axis becomes 0.61 . calculate the new rate of spin.

Correct question is;

A ballet dancer spins with 2.4 rev/s with her arms outstretched,when the moment of inertia about axis of rotation is I. With her arms folded,the moment of inertia about the same axis becomes 0.6I about the same axis. Calculate the new rate of spin.

4 rev/s

Explanation:

We are given;

Initial Angular velocity; ω_i = 2.4 rev/s

Initial moment of inertia; I_i = I

Final moment of inertia; I_f = 0.6I

From conservation of angular momentum, we have;

I_i × ω_i = I_f × ω_f

Where ω_f is the new rate of spin.

Thus, let's make it the subject to get;

ω_f = (I_i × ω_i/I_f)

Plugging in relevant values, we have;

ω_f = (I × 2.4/0.6I)

I will cancel out to give;

ω_f = 2.4/0.6

ω_f = 4 rev/s

if the thermos has a vacuum innner, then heat through conv currents and conduction are reduced = vacuum flask

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.