Speed of a mass falling into a star given the mass and radius of the star

Click For Summary
The discussion revolves around calculating the speed of a mass falling into a star using the gravitational formula. A participant attempted to use the equation but arrived at an incorrect result of 1.55*10^-5. Others suggest checking the calculations and emphasize the importance of including units in the equation. There is a consensus that ensuring proper unit usage is crucial for accurate results. The conversation highlights the need for clarity in applying gravitational equations in astrophysics.
TobiasZed
Messages
1
Reaction score
0
Homework Statement
Beginning at rest at an extremely large separation, a ball is released and allowed to fall toward a star of mass 3.90E+30 kg and radius 5.70E+7 m. What is the speed of the ball when it reaches the surface?
Relevant Equations
square root of (2*G*M)/(r)
I tried the square root of ((2)(6.67*10^-11)(3.90E+30))/(5.70E+7)
I got 1.55*10^-5 and that is wrong. Maybe I am using the wrong equation but this is the one of professor gave me and I don't know what I am doing wrong :-(
 
Physics news on Phys.org
Check your calculation.
 
… and use units!
 

Similar threads

Finding r of a Jovian-synchronous orbit and escape velocity
  • · Replies 7 ·
Replies
7
Views
2K
Extra speed necessary to orbit at 970 km
  • · Replies 8 ·
Replies
8
Views
2K
Two stars rotating about a centre of mass -- Find speed
  • · Replies 11 ·
Replies
11
Views
2K
Calculating magnetic field given dl, current, and radius vector
  • · Replies 1 ·
Replies
1
Views
990
Calculate the Orbital Radius of a Planet
  • · Replies 1 ·
Replies
1
Views
10K
Intensity of Stars and the Inverse Square Law Problem
  • · Replies 10 ·
Replies
10
Views
3K
Centripetal Acceleration of Satellite
  • · Replies 7 ·
Replies
7
Views
3K
Molecular speed distribution - most probable speed V
  • · Replies 13 ·
Replies
13
Views
1K
-- The drawing shows three particles far away from....
  • · Replies 7 ·
Replies
7
Views
4K
Finding the astronaut's weight on a planet's surface
  • · Replies 9 ·
Replies
9
Views
3K