牛頓第二定律的英文表述可以是：
1. Newton's Second Law of Motion
2. Force equals mass times acceleration
3. The second law of motion states that the rate of change of momentum is directly proportional to the applied force
其中，“motion”可以翻譯為“運(yùn)動”，“rate of change”可以翻譯為“變化率”，“momentum”可以翻譯為“動量”，“applied force”可以翻譯為“作用力”。
Example:
Question: What are Newton's Laws of Motion and how do they apply to a projectile?
Answer:
Newton's Laws of Motion state that objects in motion tend to remain in motion in a straight line unless acted upon by an external force. The first law of motion, also known as the law of inertia, states that an object will continue to move at a constant velocity unless acted upon by an external force.
When a projectile is fired from a gun, it experiences a force from the gunpowder that propels it forward. This force is called the "net force" and is equal to the product of the mass of the projectile times the acceleration due to gravity (g) times the time that the projectile is in motion. This force acts on the projectile during its entire flight, causing it to accelerate in a straight line.
The second law of motion states that the amount of force required to accelerate an object is directly proportional to its mass and inversely proportional to its acceleration. Therefore, if the projectile's mass is increased, then more force is required to accelerate it, and vice versa.
In conclusion, Newton's Laws of Motion apply to projectiles because they describe how objects respond to external forces and how force and mass are related.
