Problem Graphic

Ann is living in a dormitory room, and she has a small fan in the room. On a summer day, she turns on her fan before leaving for classes, to cool the room before she comes back in the evening. Does it work?

What is known:

• The size of the room is 4 m x 6 m x 6 m
• The power of the fan is 150 W
• She leaves at 8:00 am and comes back at 6:00 pm
• The room temperature is 15 ^oC when she leaves in the morning

• What will the temperature of the room be when Ann comes back in the evening?

• Consider the air in the room as a system
• Use specific heat values at the average room temperature
• All the energy from the fan becomes internal energy of the air in the room