- #1
littlehonda
- 10
- 0
Homework Statement
a particle of mass m is attracted to the origin by a force F=-k/r^2
find the time t for the mass to reach the origin
Homework Equations
[tex]\Delta[/tex]U= U-U0 = [tex]\int[/tex][tex]\textbf{F}[/tex](r) dr
The Attempt at a Solution
I found [tex]\Delta[/tex]U by [tex]\Delta[/tex]U= U-U0 = [tex]\int[/tex]F(r) dr and by following the convention r0=[itex]\infty[/itex] U([itex]\infty[/itex])=0
so [tex]\Delta[/tex]U = [tex]\frac{-k}{r}[/tex]
-[tex]\Delta[/tex]U=[tex]\textbf{W}[/tex]
not sure what to do now but i think I am just missing some easy steps. I know I have to equate this with 1/2mv^2 and then probably take a time derivative...