Understanding the Concepts

* Newton's Second Law: This law states that the force acting on an object is equal to its mass times its acceleration (F = ma).

* Force (F): A push or pull that can change an object's motion. Measured in Newtons (N).

* Mass (m): A measure of an object's inertia (resistance to change in motion). Measured in kilograms (kg).

* Acceleration (a): The rate of change of velocity. Measured in meters per second squared (m/s²).

Solving the Problem

1. Identify the knowns:

* Force (F) = 20 N

* Acceleration (a) = 4.0 m/s²

2. Identify the unknown:

* Mass (m)

3. Apply Newton's Second Law:

* F = ma

4. Rearrange the equation to solve for mass:

* m = F / a

5. Substitute the known values:

* m = 20 N / 4.0 m/s²

6. Calculate the mass:

* m = 5 kg

Answer: The mass of the ball is 5 kg.