Gravity Physics Example 1

Follow the full solution, then compare it with the other examples linked below.

easy

Calculate the gravitational force between Earth (

M = 5.97 \times 10^{24} \text{ kg}

) and a

1 \text{ kg}

object at Earth's surface (

r = 6.37 \times 10^6 \text{ m}

). Use

G = 6.674 \times 10^{-11} \text{ N m}^2/\text{kg}^2

1
Apply Newton's law of gravitation: $F = \frac{GMm}{r^2}$
2
Substitute: $F = \frac{6.674 \times 10^{-11} \times 5.97 \times 10^{24} \times 1}{(6.37 \times 10^6)^2}$
3
Calculate: $F = \frac{3.98 \times 10^{14}}{4.06 \times 10^{13}} \approx 9.8 \text{ N}$

Answer

F \approx 9.8 \text{ N}

This calculation confirms that

g \approx 9.8 \text{ m/s}^2

at Earth's surface. Gravity is the attractive force between any two masses, governed by the universal law of gravitation.

About Gravity

The universal attractive force between any two objects with mass, decreasing with the square of distance.

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