1. PHY115 – Sault College – Bazlurslide 1 Gravitational Force

2. PHY115 – Sault College – Bazlurslide 2 Newton’s law of gravitation Newton’s law of gravitation states that: every particle in the universe attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. If the particles have masses m1 and m2 and are separated by a distance r (from their centers of gravity), the magnitude of this gravitational force is: where: F is the magnitude of the gravitational force between the two point masses G is the gravitational constantgravitational constant m1 is the mass of the first point mass m2 is the mass of the second point mass r is the distance between the two point masses http://en.wikipedia.org/wiki/Gravity

3. PHY115 – Sault College – Bazlurslide 3 Newton’s law of gravitation If the particles have masses m1 and m2 and are separated by a distance r (from their centers of gravity), the magnitude of this gravitational force is: where: F is the magnitude of the gravitational force between the two point masses G is the gravitational constant, 6.67 × 10 −11 N m 2 kg −2gravitational constant m1 is the mass of the earth, 5.9742×10 24 kg m2 is the mass of the object, 1 kg r is the distance between the two point masses, 6,372.797 km=6,372,797 m F = (6.67 × 10 −11 N m 2 kg −2 x 5.9742×10 24 kg x 1 kg) / (6,372,797 m x 6,372,797 m) = 9.81 N

4. PHY115 – Sault College – Bazlurslide 4 Acceleration due to gravity, g F = ma a = F / m = 9.81 N / 1kg = 9.81 N/kg

5. PHY115 – Sault College – Bazlurslide 5 1 Newton A newton is the amount of force required to accelerate a mass of one kilogram by one metre per second squared. acceleratemasskilogram metre per second squared Examples 1 N is the force of Earth's gravity on an apple with a mass of about 102 g. On Earth's surface, a mass of 1 kg exerts a force of 9.8 N on its support. http://en.wikipedia.org/wiki/Newton