For a physics problem involving forces and Universal Gravitation, the formula you use depends on the specific details of the question, but here are some common formulas related to the two concepts:

1. Newton’s Second Law of Motion (Average Force)

To find the average force acting on an object, you can use:

$F = \frac{\Delta p}{\Delta t} = ma$

Where:

• $F$ is the force,
• $m$ is the mass of the object,
• $a$ is the acceleration, and
• $\Delta p$ is the change in momentum, $\Delta t$ is the change in time.

For a given problem, if the mass and acceleration are provided, this formula is used to find the average force acting.

2. Universal Law of Gravitation

If the force in question is due to gravity, and you're looking to calculate the gravitational force between two masses, use:

$F_g = G \frac{m_1 m_2}{r^2}$

Where:

• $F_g$ is the gravitational force,
• $G$ is the gravitational constant $(6.674 \times 10^{-11} \, \text{N m}^2/\text{kg}^2)$,
• $m_1$ and $m_2$ are the masses of the two objects,
• $r$ is the distance between the centers of the two objects.

If you're asked to find the magnitude of the average net force, you would apply the appropriate context — for example, whether the force is due to gravity, friction, or a combination of different forces.

To summarize:

• Use Newton’s Second Law $F = ma$ when the question involves acceleration or motion.
• Use Universal Gravitation $F_g = G \frac{m_1 m_2}{r^2}$ when the force is gravitational.

Do you have any specifics or need help with a particular example? I'd be happy to assist further!

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Follow-up questions:

1. How does Newton's second law relate to calculating net force?
2. What is the significance of the gravitational constant $G$ in the Universal Gravitation formula?
3. How do you find acceleration if you're given mass and force?
4. What are common situations where the Universal Law of Gravitation is used in physics problems?
5. Can the average force be used to calculate momentum change over time?

Tip: Always ensure you are using the correct units for mass (kg), distance (m), and force (N) to avoid any calculation errors!