8. Which of these plastics is a themoplastic - melts or softens with heat. Acrylic
Bakelite
Polyester resin
Melamine
Epoxy Resin

Could someone please help me, this is very urgent, I will pay an extra bonus if done correct.

What difference(s) did you notice using a pneumatic circuit over hydraulic circuit.explain why the pneumatic piston stumbles when it hits an obstacle.

Thermal stresses are developed in a metal when its a) initial temperature is changed b) final temperature is changed c) density is changed d) thermal deformation is prevented e) expansion is prevented f) contraction is prevented

Aquick transition of the operating speed of a shaft from its critical speed will whirl amplitude. (a) increase (b) limit (c) not affect (d) zero