I need help on this question please you guys

The y form of iron is known as: a) ferrite b) cementite c) perlite d) austenite

Water at the rate of 1 kg/s is forced through a tube with a 2.5 cm inner diameter. the inlet water temperature is 15°c, and the outlet water temperature is 50°c. the tube wall temperature is 14°c higher than the local water temperature all along the length of the tube. what is the length of the tube?

Vibration monitoring this technique uses the noise or vibration created by mechanical equipment and in seme cases by plant systems to detemine their actual condtion. a)- true b)- false