2.Write an abstract class Vehicle which has two data fields: speed(int) and costPerKM(double), get/set methods for each data field and a constructor method that initializes speed to 0 and costPerKM to 0.0. The vehicle class also has an abstract method getTripDuration() that has a double type parameter(for the trip distance) and return type is also double.

3. write a child class of vehicle named Plane which has a data fieild extraCost(double) and the corresponding get/set methods. The plane calss has two construtor method: a default constructor tht set/initialize speed to 0, costPerKM to 0.0, and the other constructor sets/initialize the three data fields with the corresponding paramenteres. The Plane class has another method named getCost() that has one double type parameter for the distance and retutrns the trip cost by taking a plane i:e cost=costPerKm*distance+extraCost. The class implements the getTripDuration() method that calcuklates the trip duration by adding half an hour(for taking off, landing etc.) to the normal flight duration(distance divided by speed).