Universal Gravitation

What is the equation for Newton's Second Law, converted to relate to gravity?

• Fg = ma

• Fg = mg

• Fg = mv

• Fg = m/a

What does the variable 'g' represent in the force of gravity equation?

• Force of friction
• Acceleration due to gravity (9.81 m/s²)

• Distance between two objects
• Mass of the object

What is Newton's Universal Law of Gravitation?

• Only large masses attract each other with a constant force regardless of distance.
• The force that every mass exerts on every other mass, with a force proportional to the product of their masses.

• Every mass repels every other mass with a force proportional to the sum of their masses.
• Gravity only acts on objects that are in motion.

KEY POINT: The gravitational acceleration constant (little g) for the Earth is 9.81 m/s². Every planet has a different gravitational constant. For example, the gravitational constant for Mars is 3.72 m/s².

This is TOTALLY DIFFERENT from BIG G, which is the Universal Gravitational Constant that applies to all bodies with mass. The UGC is 6.67 x 10 ^-11 Newtons.

So, Little G is the acceleration due to gravity of a free falling object towards a SPECIFIC body with mass; while Big G is the actual force of gravity a mass exerts on another mass.

• I understand this

• I am totally lost.

• I like bunnies.

In Newton's equation for Universal Gravitation, what does r represent?

• R represents the gravitational constant.
• R represents the mass of the larger object.
• R represents the acceleration due to gravity.
• R represents the distance between the centers of two masses.

What happens to the gravitational attraction if only one object exists in a universe?

• The gravitational attraction would be constant.
• The gravitational attraction would be strong.
• The gravitational attraction would be infinite.
• The gravitational attraction would be zero.

How does the force of gravity between two objects relate to Newton's third law?

• The force of gravity is only present when objects are in motion.
• Gravity acts in a single direction, not equal and opposite.
• The force of gravity between two objects is equal and opposite.

• Newton's third law states that gravity is a weak force.

When should the force of gravity equation ( F_g = mg ) be used?

• When measuring the speed of an object falling from a height.
• When calculating the weight of an object in space.
• When determining the mass of an object without gravity.
• When calculating the gravitational force on a mass near a planet's surface.