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A body rotates around a self-contained axis once every 58 days. It also revolves around
an external point, 58 million kilometers away every 88 days. It has a mass of 3.3x1023
kilograms.
a. What is the centripetal force acting on this object in Newtons?
b. The object changes its rotational period from once every 58 days to once every
34 days over 7 years. What is the angular acceleration during this time in rad/s2?
c. Using your response from part b, how many complete rotations will the object
make over those 7 years?

Answer :

skyluke89

a) The centripetal force is [tex]2.99\cdot 10^{22} N[/tex]

b) The angular acceleration is [tex]4.03\cdot 10^{-15} rad/s^2[/tex]

c) The number of complete rotations over 7 years is [tex]1.57\cdot 10^{31}[/tex]

Explanation:

a)

First of all, let's convert all the given quantities into SI units:

[tex]r = 58 mil. km = 58 \cdot 10^6 km = 58\cdot 10^9 m[/tex] is the radius of the circular path of the body

[tex]T=58 days = 58 \cdot (24\cdot 60 \cdot 60 )=5.01 \cdot 10^6 s[/tex] is the period of revolution

[tex]m=3.3\cdot 10^{23}kg[/tex] is the mass of the body

From these data, we can calculate first the angular velocity of the body, which is given by:

[tex]\omega=\frac{2\pi}{T}=\frac{2\pi}{5.01\cdot 10^6}=1.25\cdot 10^{-6}rad/s[/tex]

And now we can calculate the centripetal force, which is given by:

[tex]F=m\omega r^2 = (3.3\cdot 10^{23})(1.25\cdot 10^{-6})^2(58\cdot 10^9)=2.99\cdot 10^{22} N[/tex]

b)

We already calculated the initial angular velocity of the body, which was

[tex]\omega = 1.25\cdot 10^{-6} rad/s[/tex]

Here we are said that the new period of revolution is

[tex]T'=34 days = 34 \cdot (24\cdot 60 \cdot 60 )=2.94 \cdot 10^6 s[/tex]

This means that the new angular velocity is

[tex]\omega'=\frac{2\pi}{T'}=\frac{2\pi}{2.94\cdot 10^6}=2.14\cdot 10^{-6}rad/s[/tex]

And this change occurs in a time interval of

[tex]t=7 years = 7 \cdot 365 \cdot 24 \cdot 60 \cdot 60 = 2.21\cdot 10^8 s[/tex]

Therefore, the angular acceleration of the body is

[tex]\alpha = \frac{\omega'-\omega}{t}=\frac{2.14\cdot 10^{-6} -1.25\cdot 10^{-6}}{2.21\cdot 10^8}=4.03\cdot 10^{-15} rad/s^2[/tex]

c)

To solve this part, we have to use the following suvat equation for rotational motions:

[tex]\theta= \omega t + \frac{1}{2}\alpha t^2[/tex]

where:

[tex]\theta[/tex] is the angular displacement covered in a time t

[tex]\omega=1.25\cdot 10^{-6}rad/s[/tex] is the initial angular velocity

[tex]t=2.21\cdot 10^8 s[/tex] is the time interval

[tex]\alpha=4.03\cdot 10^{-15} rad/s^2[/tex] is the angular acceleration

Substituting into the equation,

[tex]\theta= (1.25\cdot 10^{-6})(2.21\cdot 10^8) + \frac{1}{2}(4.03\cdot 10^{15})(2.21\cdot 10^8)^2=9.84\cdot 10^{31} rad[/tex]

And converting into revolutions,

[tex]\theta=\frac{9.84\cdot 10^{31} rad}{2\pi rad/rev}=1.57\cdot 10^{31} rev[/tex]

Learn more about circular motion:

brainly.com/question/2562955

brainly.com/question/6372960

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