Answer:
4.44586579653 rpm
Explanation:
G = Gravitational constant = 6.67 × 10⁻¹¹ m³/kgs²
M = Mass of Europa = [tex]4.8\times 10^{22}\ kg[/tex]
R = Radius of Europa = [tex]\dfrac{3138000}{2}\ m[/tex]
r = Radius of arm = 6 m
[tex]\omega[/tex] = Angular velocity
Acceleration due to gravity is given by
[tex]a=\dfrac{GM}{R^2}\\\Rightarrow a=\dfrac{6.67\times 10^{-11}\times 4.8\times 10^{22}}{\left(\dfrac{3138000}{2}\right)^2}\\\Rightarrow a=1.30053242374\ m/s^2[/tex]
Now, equating the above value with the motion of the arm
[tex]a=\omega^2 r\\\Rightarrow \omega=\sqrt{\dfrac{a}{r}}\\\Rightarrow \omega=\sqrt{\dfrac{1.30053242374}{6}}\\\Rightarrow \omega=0.465569977508\ rad/s[/tex]
Converting to rpm
[tex]0.465569977508\times\dfrac{60}{2\pi}=4.44586579653\ rpm[/tex]
The angular speed of the arm is 4.44586579653 rpm