How Does Changing a Planet's Radius Affect Its Mass?

  • Thread starter Thread starter unseenoi
  • Start date Start date
  • Tags Tags
    Mass Radius
AI Thread Summary
Changing a planet's radius affects its mass based on the volume and density relationship. If a planet's radius is one-fifth that of Earth, its volume is significantly reduced, calculated using the formula for the volume of a sphere. Assuming the same density as Earth, the mass can be determined by multiplying the volume ratio by Earth's mass. The discussion emphasizes understanding the density formula, where density equals mass divided by volume. The key takeaway is that mass is not directly proportional to radius but is influenced by volume and density.
unseenoi
Messages
8
Reaction score
0

Homework Statement



I know this is a dumb question but if the radius of a planet is one-fifth of the Earth's radius. what is the mass of the planet.

Earth mass => 5.97 *1024
earth radius => 6.38 *106

The Attempt at a Solution



my answer: 5.97 *1024(1/10)
 
Last edited:
Physics news on Phys.org
unseenoi said:

Homework Statement



I know this is a dumb question but if the radius of a planet is one-fifth of the Earth . what is the mass of the planet.

Earth mass => 5.97 *1024
earth radius => 6.38 *106

The Attempt at a Solution



my answer: 5.97 *1024(1/10)

And incorrect.

If the radius is 1/5 and it has the same density as earth, then what would the mass be?

Think about the ratio of the volume between the 2 and then multiply that appropriately by Earth mass.
 
Can u please give me more details.
 
density = mass/volume --> \rho=m/v

What is the formula for determining the volume of a sphere? Given the Earth's radius, what is its volume?
 

Thread 'Rolling without slipping on a curved surface'

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 .
View full post »

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

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...
View full post »
Thread 'A bead-mass oscillatory system problem'

Thread 'A bead-mass oscillatory system problem'

I can't figure out how to find the velocity of the particle at 37 degrees. Basically the bead moves with velocity towards right let's call it v1. The particle moves with some velocity v2. In frame of the bead, the particle is performing circular motion. So v of particle wrt bead would be perpendicular to the string. But how would I find the velocity of particle in ground frame? I tried using vectors to figure it out and the angle is coming out to be extremely long. One equation is by work...
View full post »

Similar threads

How do mass and radius affect gravitational pull on planets?
Replies
6
Views
2K
Radius of a planet with the same density as Neptune
Replies
13
Views
3K
Calculating the Length of a Space Elevator Rope
Replies
18
Views
2K
Finding the radius in the universal gravity equation
Replies
7
Views
2K
Calculate magnetic dipole of other planets relative to the Earth
Replies
4
Views
1K
What was the speed of Sputnik I at its perigee?
Replies
18
Views
3K
Radius of a planet, given the density
Replies
3
Views
25K
Fundamental Forces Problem: Acceleration from Planet
Replies
9
Views
1K
Universal Gravitation and/or Tidal Forces?
Replies
1
Views
1K
Gravitational Acceleration given mass and radius
Replies
3
Views
2K

Hot Threads

Recent Insights

Back
Top