Repeat Problem 7-83 for the plates oriented in a horizontal position with the 50C surface as the

Question:

Repeat Problem 7-83 for the plates oriented in a horizontal position with the 50◦C surface as the lower plate.
Problem 7-83
Two vertical plates 50 by 50 cm are separated by a space of 4 cm that is filled with water. The plate temperatures are 50 and 20oC. Calculate the heat transfer across the space.