Potential energy which is the stored energy an object has waiting to be used
The gravitational force between <em>m₁</em> and <em>m₂</em> has magnitude

while the gravitational force between <em>m₁</em> and <em>m₃</em> has magnitude

where <em>x</em> is measured in m.
The mass <em>m₁</em> is attracted to <em>m₂</em> in one direction, and attracted to <em>m₃</em> in the opposite direction such that <em>m₁</em> in equilibrium. So by Newton's second law, we have

Solve for <em>x</em> :

The solution with the negative square root is negative, so we throw it out. The other is the one we want,

I think that mechanism is called a <em>"lens turret"</em>.
Answer:
-0.481 m/s^2
Explanation:
The force equation of this problem is given as:
F - W = ma
where F = upward force holding the clarinet bag
W = downward force (weight of the clarinet)
The mass of the clarinet bag is 3.010 kg, therefore, its weight is:
W = mg
W = 3.010 * 9.8 = 29.498
F = 28.05 N
Therefore:
28.05 - 29.498 = 3.010 * a
-1.448 = 3.010a
=> a = -1.448 / 3.010
a = -0.481 m/s^2
The acceleration of the bag is downward.
Here is the full question:
The rotational inertia I of any given body of mass M about any given axis is equal to the rotational inertia of an equivalent hoop about that axis, if the hoop has the same mass M and a radius k given by:

The radius k of the equivalent hoop is called the radius of gyration of the given body. Using this formula, find the radius of gyration of (a) a cylinder of radius 1.20 m, (b) a thin spherical shell of radius 1.20 m, and (c) a solid sphere of radius 1.20 m, all rotating about their central axes.
Answer:
a) 0.85 m
b) 0.98 m
c) 0.76 m
Explanation:
Given that: the radius of gyration
So, moment of rotational inertia (I) of a cylinder about it axis = 





k = 0.8455 m
k ≅ 0.85 m
For the spherical shell of radius
(I) = 




k = 0.9797 m
k ≅ 0.98 m
For the solid sphere of radius
(I) = 




k = 0.7560
k ≅ 0.76 m