Question

A boy sitting in an open car moving with the constant speed throws a ball straight up into the air.

Q: Answer-A boy sitting in an open car moving with the constant speed throws a ball straight up into the air.

The moment ball is thrown, it is moving with the velocity of the car. According to the inertia of motion it will continue to move in the same direction with the same velocity. As the ball is moving up and the down it will maintain its forward motion but practically it is not possible to neglect the resistance caused by air friction. So, the ball will fall behind him.