How to find trajectory as a function of time with energy

Cocoleia
Messages
293
Reaction score
4

Homework Statement


I am given that an object of mass m has an attractive force F=-A/x^2 acting on it, where A is a constant and x>0. I need to find the potential energy. After i need to suppose initial conditions (x0, v0) such that total energy=0. I need to find the trajectory x(t) with v>0

Homework Equations


Potential energy = mgh

The Attempt at a Solution


So far I said that F=ma and then found the acceleration. I integrated the acceleration to find the speed, then I integrated that to find the position, which is A/m ln(x). I said that the potential energy = gAln(x). From this point I am stuck, I can't figure out how to find the trajectory as a function of time.
 
on Phys.org
F=ma gives you the acceleration as function of distance. Converting this to acceleration as function of time (what you need for the integration steps) is not trivial.
Cocoleia said:
Potential energy = mgh
That does not work. This is not a "gravity on a lab scale" setup.
Cocoleia said:
then I integrated that to find the position, which is A/m ln(x)
Your position depends on the logarithm of the position?
 
mfb said:
F=ma gives you the acceleration as function of distance. Converting this to acceleration as function of time (what you need for the integration steps) is not trivial.
That does not work. This is not a "gravity on a lab scale" setup.
Your position depends on the logarithm of the position?
Ok. Then how will I find the potential energy ?
 
The definition of potential energy directly gives a way to calculate it based on the force.
 

Similar threads

Replies
2
Views
1K
Replies
15
Views
2K
  • · Replies 18 ·
Replies
18
Views
2K
  • · Replies 15 ·
Replies
15
Views
2K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
2
Views
2K
Replies
9
Views
1K
  • · Replies 6 ·
Replies
6
Views
2K