Answer 1

Only car3 and car2 is equal.
car1 = new Car();
car1 is now the value of a new instance of the class car.

car2 = new Car();
Same thing with car2, the instances are independant.

car3 = car2
This assigns the value of the reference (or 'memory location') of car2 to car3.
So, lets say we did:
car2.setSpeed(100);
That would be the same as doing:
car3.setSpeed(100);

Both the variables point to the same object.
car2 == car3 // true