There is strong evidence that Europa, a satellite of Jupiter, has a liquid ocean beneath its icy surface. Many scientists think we should land a vehicle there to search for life. Before launching it, we would want to test such a lander under the gravity conditions at the surface of Europa. One way to do this is to put the lander at the end of a rotating arm in an orbiting earth satellite. If the arm is 4.25 m long and pivots about one end, at what angular speed (in rpm) should it spin so that the acceleration of the lander is the same as the acceleration due to gravity at the surface of Europa? The mass of Europa is 4.80 x 10^{22} kg and its diameter is 3120 km.



Answer :

The angular speed of the lander at the end of the rotating arm is 4.98 rpm.

It is given to us that -

The radius of the rotating arm = 4.25 m

Mass of the Europa = [tex]4.80 * 10^{22}[/tex] kg

Diameter of the Europa = 3120 km

=> Radius of the Europa = 3120/2 = 1560 km = 1,560,000 m

We have to find out the angular speed (in rpm) at which the rotating arm should spin so that the acceleration of the lander is the same as the acceleration due to gravity at the surface of Europa.

Firstly, we have to find out the acceleration due to gravity of the Europa. We know that the force on the Europa can be given as -

[tex]F = Mg\\= > Mg = \frac{G*m*M}{R^{2} } \\= > g = \frac{G*m}{R^{2}}\\= > g = \frac{(6.67 * 10^{-11} )*(4.80*10^{22} )}{1560000^{2} } \\= > g = 1.19 m/s^{2}[/tex] ----- (1)

It is given to us that -

Acceleration of the lander = Acceleration due to gravity at the Europa

[tex]= > a_{l} = g\\= > a_{l} = 1.19 m/s^{2}[/tex] ----- (2)    [From equation (1)]

Now, to calculate the angular speed of the lander, we can use the formula as -

[tex]= > a_{l} = w^{2} r\\= > w^{2} = \frac{a_{l} }{r} \\[/tex] ----- (3)

where,

[tex]a_{l}[/tex] = Acceleration of the lander

[tex]w[/tex] = angular speed of the lander

r = radius of the rotating arm

Substituting the values of [tex]a_{l}[/tex] from equation (2) and r in equation (3), we have -

[tex]w^{2} = \frac{a_{l} }{r}\\= > w^{2} = \frac{1.19 }{4.25}\\= > w^{2} = 0.28\\= > w = 0.529 rad/s[/tex]

In order to convert the angular speed in rpm, we have to use -

[tex]w = 0.529 rad/s\\= > w = 0.529 * \frac{1 rev * 60 s}{2\pi rad*1 min}\\ = > w = 4.98 rpm[/tex]

Therefore, the angular speed of the lander at the end of the rotating arm is 4.98 rpm.

To learn more about angular speed visit https://brainly.com/question/14663644

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