Answer:
4.44 rpm
Explanation:
= Angular speed
G = Gravitational constant = 6.67 × 10⁻¹¹ m³/kgs²
r = Radius of Europa = 
R = Radius of arm = 6 m
The acceleration due to gravity is given by

Here the centripetal acceleration of the arm and acceleration due to gravity are equal


Converting to rpm


The angular speed of the arm is 4.44 rpm
Tooth fillings are often made of gold or porcelain because these materials are nonreactive.
b. nonreactive.
Answer:
F = 0.1575 N
Explanation:
When the third sphere touches the first sphere, the charge is distributed between both spheres, then now the first sphere has only half of his original charge.
In this moment then
Sphere one has a charge = Q/2
Sphere three has a charge = Q/2
Now when the third sphere touches the second sphere again the charge is distributed in a manner that both sphere has the same charge.
How the total charge is Q = Q/2 + Q = 3/2Q, when the spheres are separated each one has 3/4Q
Sphere two has a charge = 3/4Q
Sphere three has a charge = 3/4Q
The electrostatic force that acts on sphere 2 due to sphere 1 is:
F = 
F= 
how
= 0.42
Then
F = 
F = 0.1575 N
Don’t know sorry I’m just trying not a good person