Key relationship
F=Gm₁m₂/r²; gA=Gm₁/r².
Physics · Class 11
Separate two attracting masses
Every pair of masses attracts. The inverse-square relationship means doubling separation reduces the force to one quarter. Changing either mass scales the force linearly.
Open the interactive experiment →Separate two attracting masses
ஈர்ப்பு விசை நிறைகளின் பெருக்கலுக்கு நேர்விகிதத்திலும் இடைத்தொலைவின் வர்க்கத்திற்கு எதிர்விகிதத்திலும் இருக்கும்.
Key notes, relationships and model limits
Remember
Every pair of masses attracts. The inverse-square relationship means doubling separation reduces the force to one quarter. Changing either mass scales the force linearly.
Common trap
The distance in the law is between centres for spherical masses.
Model limits
Separated spherical bodies treated as point masses; centre-to-centre distance is much larger than their radii. Newtonian gravity.
What you will learn
Explore inverse-square attraction and distinguish force from field.
Try the experiment
Try both scenarios, change one control, and predict the result before checking the graph and readouts.
Think of it this way
Change one input while keeping the others fixed, as you would in a controlled experiment.
Worked example
For 10⁷ kg and 2×10⁷ kg at 100 m, F=6.6743×10⁻¹¹×2×10¹⁴/10⁴=1.33486 N.
Why this matters
The model connects separate two attracting masses with an observable reading. Check the equation and assumptions before applying it.
Before you start
SI units · algebra · graph reading
Check your understanding
If separation doubles with fixed masses, what happens to force?
- It becomes one half
- It becomes one quarter
- It doubles
Read the explanation
F is proportional to 1/r², hence F(2r)=F(r)/4.
Course connection: Class XI Chapter 7. Consult the roadmap for CBSE, NEET, JEE Main and Advanced scope.