COMMUNITY I NEED YOUR HELP!! :(

If a balloon is taken outside on a very cold day, what will occur?

For the car in the picture ,in which direction is the normal force? -into the screen -down -out of the screen -up

8.29 two streams containing pyridine and acetic acid at 25°c are mixed and fed into a heat exchanger. due to the heat-of-mixing effect, it is desired to reduce the temperature after mixing to 25°c using a stream of chilled ethylene glycol as indicated in the diagram. calculate the mass flow rate of ethylene glycol needed. the heat capacity of ethylene glycol at these conditions is approximately 2.8 kj/(kg k), and the enthalpy change of mixing (δmixh) is given below.