What is the angular momentum of the moon orbiting an Earth-like planet?

AI Thread Summary
The discussion focuses on calculating the angular momentum of a moon orbiting an Earth-like planet, given its mass, orbital period, and radius. The key formula for angular momentum is L = r x p, where p is the linear momentum (p = mv). The moment of inertia is calculated using I = 2/5mr^2, leading to I = 1.37 x 10^33 kgm^2 for the moon. The angular velocity is derived from the orbital period, resulting in ω = 2.66 x 10^-6 rad/s. Ultimately, the angular momentum is determined to be 3.65 x 10^27 kgm^2/s.
NX805
Messages
1
Reaction score
0
Hi, can anyone help me get started on this problem...I am totally lost and don't know what equation to use...thanks a lot

There is a moon orbiting an Earth-like planet. The mass of the moon is 6.23 x 10^22 kg, the center-to-center separation of the planet and the moon is 649000 km, the orbital period of the moon is 29.3 days, and the radius of the moon is 1040km. What is the angular momentum of the moon about the planet.
 
Physics news on Phys.org
they are talkin about point mass angular momentum

L = r x p (the linear v is 90 degrees to the radius therefore) = r*p while p = mv and u can figure out the linear veloctiy useing the orbital period.

29.3 days to go 2pi radians so... w = 2pi/(29.3 days) and v = wr so u get...

L = r^2 m (2pi)/(29.3 days)
 


To solve this problem, we can use the equation for angular momentum, which is L = Iω, where L is the angular momentum, I is the moment of inertia, and ω is the angular velocity.

First, we need to calculate the moment of inertia of the moon. This can be done using the formula I = 2/5mr^2, where m is the mass of the moon and r is its radius. Plugging in the given values, we get I = 2/5(6.23 x 10^22 kg)(1040km)^2 = 1.37 x 10^33 kgm^2.

Next, we need to find the angular velocity of the moon. This can be calculated using the formula ω = 2π/T, where T is the orbital period. Plugging in the given value of 29.3 days (which needs to be converted to seconds), we get ω = 2π/(29.3 days * 24 hours/day * 60 minutes/hour * 60 seconds/minute) = 2.66 x 10^-6 rad/s.

Now, we can plug in our calculated values into the equation for angular momentum: L = (1.37 x 10^33 kgm^2)(2.66 x 10^-6 rad/s) = 3.65 x 10^27 kgm^2/s.

Therefore, the angular momentum of the moon orbiting an Earth-like planet is 3.65 x 10^27 kgm^2/s.
 
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
Back
Top