A pin fin of uniform, cross-sectional area is fabricated of an aluminum alloy ( 160 W/m·K). The fin diameter is 7 mm, and the fin is exposed to convective conditions characterized by 220 W/m2·K. It is reported that the fin efficiency is 0.65. Determine (a) the fin length and the fin effectiveness . Account for tip convection.

In a system, when potential energy decreases, then entropy also decreases. true false

Choose the most likely outcome of this scenario: jen decided to go bike riding without a helmet. while no one is around during her ride, she is thrown from her bike when her wheel goes into a pothole. she is not injured, but she is terrified to get back on her bike. what happens next? a. her physical health is affected even though she wasn't hurt. b. her mental and emotional health are affected because she is afraid to get back on her bike. c. her social health is affected because she is worried her friends saw the fall. d. her overall health is not affected at all by her fall.

5g of ammonium nitrate was dissolved in 60g of water in an insulated container. the temperature at the start of the reaction was 23.0°c and at the end it was 19.0°c. calculate the energy absorbed by the reaction.