tính toán để quấn dây cho một máy biến áp có điện áp cuộn sơ cấp là 220V cuộn thứ cấp có điện áp là 6V, 12V cho sắt tốt, mẫu lá thép bọc có a = 3 cm

Fluids at rest possess no flow energy. a)- true b)- false

Coiled springs ought to be very strong and stiff. si3n4 is a strong, stiff material. would you select this material for a spring? explain.

Describe one experiment in which the glass transition temperature and melting temperature of a totally amorphous thermoplastic material can be determined. show the relevant experimental results in a diagram which should be properly annotated with the two temperatures clearly marked. what is likely to happen to the curve in the diagram if the amorphous polymer is replaced by a thermosetting type?