Here's how to solve this problem using Newton's Second Law of Motion:

Newton's Second Law:

* F = m * a

Where:

* F is the force applied (in Newtons)

* m is the mass of the object (in kilograms)

* a is the acceleration of the object (in meters per second squared)

Solving for Mass:

1. Rearrange the formula:

To find the mass (m), we need to isolate it:

m = F / a

2. Plug in the values:

m = 15 N / 5.0 m/s²

3. Calculate:

m = 3 kg

Therefore, the mass of the object is 3 kg.