Physics SL
5
Chapters
329
Notes
Theme A - Space, Time & Motion
Theme B - The Particulate Nature Of Matter
Theme C - Wave Behaviour
Theme D - Fields
Theme E - Nuclear & Quantum Physics
Physics SL
Theme D - Fields
Understanding Gravitational Potential & Field Strength in Cosmic Systems
602 words
4 mins read
Last edited on 5th Nov 2024
Table of content
Understanding gravitational potential
- Gravitational potential at a point (Vg) at a distance (r) from a point object of mass (M) is given by Vg = - GM/r.
- When we differentiate this equation with respect to r, we get dVg/dr = GM/r2. The right-hand side of this expression is the value for g due to a point object of mass M at a distance of r from the object: g = - GM/r2.
- In simple terms, gravitational potential is related to the work done against the gravitational field in moving from one point to another.
Two graphical links between field strength & potential
- Gravitational Field Strength vs Distance
- This graph shows how the field strength changes with distance from the point mass.
- The change in gravitational potential (moving from P to Q) is equal to -g × Δr. This represents the area between the curve (1/r2 shaped) and the distance axis.
- This area is negative, but the negative sign in -g × Δr cancels it out to give a positive value. This shows that energy is transferred into the gravitational system when moving from P to Q.
- Gravitational Potential vs Distance
- In this graph, the gravitational field strength at a point is equal to -ΔVg/Δr, which is the gradient of the graph at that point.
- The negative sign shows that the direction of the gravitational field strength is opposite to the direction in which gravitational potential increases.
Real-world example - binary star system
- A binary star system consists of two stars bound together by gravity.
- To study the nature of these stars, astronomers use physics principles from other themes in this course.
- They can observe visual binary systems with Earth-bound or satellite-based telescopes.
- Astronomers can also determine the nature of spectroscopic binaries using emission and absorption spectral lines.
- Changes in the overall luminosity of the pair can provide important clues about the nature of the stars.
Unlock the Full Content! 
Dive deeper and gain exclusive access to premium files of Physics SL. Subscribe now and get closer to that 45 🌟
Physics SL
Theme D - Fields
Understanding Gravitational Potential & Field Strength in Cosmic Systems
602 words
4 mins read
Last edited on 5th Nov 2024
Table of content
Understanding gravitational potential
- Gravitational potential at a point (Vg) at a distance (r) from a point object of mass (M) is given by Vg = - GM/r.
- When we differentiate this equation with respect to r, we get dVg/dr = GM/r2. The right-hand side of this expression is the value for g due to a point object of mass M at a distance of r from the object: g = - GM/r2.
- In simple terms, gravitational potential is related to the work done against the gravitational field in moving from one point to another.
Two graphical links between field strength & potential
- Gravitational Field Strength vs Distance
- This graph shows how the field strength changes with distance from the point mass.
- The change in gravitational potential (moving from P to Q) is equal to -g × Δr. This represents the area between the curve (1/r2 shaped) and the distance axis.
- This area is negative, but the negative sign in -g × Δr cancels it out to give a positive value. This shows that energy is transferred into the gravitational system when moving from P to Q.
- Gravitational Potential vs Distance
- In this graph, the gravitational field strength at a point is equal to -ΔVg/Δr, which is the gradient of the graph at that point.
- The negative sign shows that the direction of the gravitational field strength is opposite to the direction in which gravitational potential increases.
Real-world example - binary star system
- A binary star system consists of two stars bound together by gravity.
- To study the nature of these stars, astronomers use physics principles from other themes in this course.
- They can observe visual binary systems with Earth-bound or satellite-based telescopes.
- Astronomers can also determine the nature of spectroscopic binaries using emission and absorption spectral lines.
- Changes in the overall luminosity of the pair can provide important clues about the nature of the stars.
Unlock the Full Content!
Dive deeper and gain exclusive access to premium files of Physics SL. Subscribe now and get closer to that 45 🌟
AI Assist
Expand
Hello there,
how can I help you today?
how can I help you today?