Benefits of using an abstract classes vs. regular class

Question

I have decided to start doing small coding projects on my own that focus on code quality instead of code quantity and have a question about the use of abstract classes.

Answer 1

This might help you, Lets consider traveler who may use any type of vehicle i.e car,cycle,bike etc...
but all vehicles moves in the same way with different speed constraints so we can have one

abstract class Avehicle    
{  
        string fuel;  
        public void move()  
{  
 sysout("moving");  
}   
} 

but all vehicles breaking system is different

interface Ivehicle    
{  

        public void breakorstop();  
}  
class Traveler    
{  
  Ivehicle v; 
//Settrers and getters   
 public drive()  
{  
v.move();  
}  
public break()  
{  
v.breakorstop();  
}  
}

So finally Car or Cycle or Bike classes can extend Avehicle and can Implement Vehicle interface