Gravitational forces and fields | AP Physics | Khan Academy

What is the fundamental nature of the gravitational force between any two masses in the universe, according to Newton's law of universal gravitation?

• It is always repulsive.

• It is always attractive.

• It can be either attractive or repulsive depending on the masses.

• It only exists between celestial bodies.

How does the magnitude of the gravitational force between two objects change if the distance between their centers is doubled?

• It doubles.

• It halves.

• It becomes four times stronger.

• It becomes one-fourth as strong.

What is the approximate value of the universal gravitational constant (G)?

• 9.8 m/s^2

• 6.67 x 10^-11 Nm^2/kg^2

• 3.00 x 10^8 m/s

• 1.60 x 10^-19 C

What is the gravitational field strength at a given point?

• The total gravitational force exerted by all masses.

• The gravitational force per unit mass at that point.

• The acceleration of an object due to gravity.

• The product of gravitational force and mass.

What are the standard SI units for gravitational field strength?

• Meters per second squared (m/s²)

• Newtons per kilogram (N/kg)

• Joules per kilogram (J/kg)

• Kilograms per meter (kg/m)

Why is the symbol 'g' used for both gravitational field strength and gravitational acceleration?

• They are fundamentally different concepts but share a common symbol for simplicity.

• They are numerically equal when no other forces are acting, and their expressions are identical.

• Gravitational field strength is a vector, while gravitational acceleration is a scalar.

• One is a cause, and the other is an effect, but their magnitudes are always proportional.

How is the strength of a gravitational field represented in a field line model?

• By the length of the field lines.

• By the color of the field lines.

• By the density (closeness) of the field lines.

• By the curvature of the field lines.