- Parent Category: 02 Newtonian Mechanics
- Category: 08 Gravity
- Created: Thursday, 20 August 2015 15:00
- Last Updated: Thursday, 25 May 2017 15:35
- Published: Saturday, 09 April 2016 15:00
- Hits: 6810
7.3.7 Gravitational Potential (symbol: ϕ and units: J kg-1)
The gravitational potential, ϕ , at a point due to the gravitational field set up by a mass M is defined as the work done per unit mass in bringing a point mass from infinity to that point.
Mathematically, it can be shown that
126.96.36.199 Equation U = mϕ1) This expression is similar to the expression for gravitational potential energy, . and they are related by U = mϕ.
188.8.131.52 Scalar quantity2) Gravitational potential is a scalar quantity. (i.e. it has no direction and a negative value simply means it is less than zero).
184.108.40.206 Always negative3) This expression implies that ϕ is also always negative (less than zero) and by convention, the gravitational potential at infinity is also taken to be zero (maximum).
220.127.116.11 Independent of test mass4) Similar to gravitational field strength , gravitational potential is also independent of the mass of the point mass, m.
18.104.22.168 Vary according to inverse law with distance r5) As distance r of the point mass from source mass increases, ϕ increases according to the equation .
7.3.8 Activity to do
|units||N kg-1 or m s-2||J kg-1|
|meaning||Gravitational force per unit mass||Gravitational potential energy per unit mass|
|equation|| towards the centre of the source mass |
|relationship to mass||Force, = mg||Potential energy, = mϕ|
|computer model if M = 500.||-6.67*500/(abs(r)*r)||-6.67*500/abs(r)|
7.3.10 ModelingTry to input your own model for potential until you achieve a close fit to the data set graph from potential.
What is the value of M is the model?
no need to key in x10-11
try something like -6.67*500/abs(r) in the equivalent for
|with best with||Chrome||Chrome||Chrome||Chrome|
|support full-screen?||Yes. Chrome/Opera No. Firefox/ Samsung Internet||Not yet||Yes||Yes|