2. State Hooke's law.
3. Describe simple harmonic motion.

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Explanation:

2.Hooke's law is a law of physics that states that the force needed to extend or compress a spring by some distance (x) scales linearly with respect to that distance—that is, where k is a constant factor characteristic of the spring, and x is small compared to the total possible deformation of the spring.

3.In mechanics and physics, simple harmonic motion is a special type of periodic motion where the restoring force on the moving object is directly proportional to the object's displacement magnitude and acts towards the object's equilibrium position.

coil wire, increase current, put iron inside the coil

if the thermos has a vacuum innner, then heat through conv currents and conduction are reduced = vacuum flask