# Gravity equation

1. Three particles each with a mass of 1 kg are at the vertices of an equilateral triangle whose sides are 1 m long. How large is the gravitational force experienced by each point particle (in G)?

Solution

The magnitude of the gravitational force experienced by one of the particles.

F12 = G (m1)(m2) / r2 = G (1)(1) / 12 = G/1 = G

F13 = G (m1)(m3) / r2 = G (1)(1) / 12 = G/1 = G

Resultant gravitational force at point 1:

F1 = √12+12 = √1+1 = √2 Newton

2. The figure below depicts three objects m1 = 6 kg; m2 = 3 kg and m3 = 4 kg lie on a straight line. Determine the magnitude and direction of the resultant gravitational force experienced by m2! (state in G)

Known:

m1 = 6 kg

m2 = 3 kg

m3 = 4 kg

gravitational constant = G

r21 = 4 m

r23 = 2 m

Wanted: F resultant gravity experienced by m2

Solution:

The gravitational force between m2 and m3:

F = G (3)(4) / 22 = G 12 / 4 = 3G

The gravitational force between m2 and m1:

F = G (3)(6) / 42 = G 18 / 16 = 1,125G

3. Object A with a mass of 1 kg and object B with a mass of 2 kg are separated by a distance of 2 m from one another. Point P is 2 m from object A and 2 m from object B. How strong is the gravitational field at point P?

Known:

mA = 1 kg

mB = 2 kg

rPA = 2 m

rPB = 2 m

Gravity constant = G

Wanted: E gravity at point P

Solution:

EPA = G (mA) / r2 = G (1) / 22 = G/4 = 0,25G

EPB = G (mB) / r2 = G (2) / 22 = 2G/4 = 0,5G

Resultant gravitational field strength at point P:

E = √0,25G2+0,5G2 = √0,0625G2+0,25G2 = √0,3125G2 = 0,56G N/kg

4. Problem: Determine the gravitational force between two objects with masses 5 kg and 10 kg that are 2 m apart. Solution: F = G x (m₁m₂) / r² = 6.67430 x 10⁻¹¹ m³ kg⁻¹ s⁻² x (5 kg x 10 kg) / (2 m)² = 8.343875 x 10⁻¹¹ N.

5. Problem: Determine the gravitational force between two objects with masses 1 kg each that are 1 m apart. Solution: F = G x (m₁m₂) / r² = 6.67430 x 10⁻¹¹ m³ kg⁻¹ s⁻² x (1 kg x 1 kg) / (1 m)² = 6.67430 x 10⁻¹¹ N.

6. Problem: Determine the gravitational force between two objects with masses 1000 kg and 2000 kg that are 3 m apart. Solution: F = G x (m₁m₂) / r² = 6.67430 x 10⁻¹¹ m³ kg⁻¹ s⁻² x (1000 kg x 2000 kg) / (3 m)² = 1.48206 x 10⁻⁸ N.

7. Problem: Determine the gravitational force between two objects with masses 500 kg and 500 kg that are 1 m apart. Solution: F = G x (m₁m₂) / r² = 6.67430 x 10⁻¹¹ m³ kg⁻¹ s⁻² x (500 kg x 500 kg) / (1 m)² = 1.668575 x 10⁻⁸ N.

8. Problem: Determine the gravitational force between two objects with masses 700 kg and 800 kg that are 2 m apart. Solution: F = G x (m₁m₂) / r² = 6.67430 x 10⁻¹¹ m³ kg⁻¹ s⁻² x (700 kg x 800 kg) / (2 m)² = 1.334860 x 10⁻⁸ N.

9. Problem: Determine the gravitational force between two objects with masses 5 kg and 10 kg that are 2 m apart. Solution: F = G x (m₁m₂) / r² = 6.67430 x 10⁻¹¹ m³ kg⁻¹ s⁻² x (5 kg x 10 kg) / (2 m)² = 8.343875 x 10⁻¹¹ N.

10. Problem: An object with a mass of 10 kg is dropped from a height. What is the acceleration due to gravity? Solution: The acceleration due to gravity is approximately 9.8 m/s² on Earth. It does not depend on the mass of the object.