Example 1 · level 1
The gravitational force between two satellites is 36 N. If the distance between them becomes 2 times, what is the new force (in N)?
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- New F = 36 ÷ 2² = 36 ÷ 4 = 9 N.
Answer: 9 N
CLASS 9 SCIENCE · GRAVITATION
Universal law of gravitation (scaling)
F = G m₁m₂ / r². Force is proportional to each mass and inversely proportional to the square of the distance.
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Worked examples
Example 2 · level 2
Two bodies attract each other with 720 N. One mass is made 2 times and the distance is made 3 times. Find the new force (in N, correct to 2 decimal places).
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- New F = 720 × 2 ÷ 9 = 160 N.
Answer: 160 N
Example 3 · level 3
Two bodies attract each other with 144 N. One mass is made 2 times and the distance between them is halved. Find the new force (in N).
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- New F = 144 × 2 × 4 = 1,152 N.
Answer: 1,152 N