Three Ways To Extend A Class

using System;

namespace ThreeWaysToExtendAClass
{
    public class Car  // What happens if this is sealed?
    {
        public string Name { get; set; }
        public int Velocity { get; set; }

        public Car(string name)
        {
            this.Name = name;
            Console.WriteLine("\nCreated a {0}", name);
            Console.WriteLine("Velocity is {0}", this.Velocity);
        }

        public void Accelerate()
        {
            this.Velocity++;
            Console.WriteLine("Accelerated {0} to velocity {1}", this.Name, this.Velocity);
        }
    }
}