If a strip of lightly cross-linked natural rubber initially at room temperature is heated in an oven, it can be observed to expand. If the same piece of rubber is stretched at room temperature to twice its original longitudinal dimensions then placed in the same oven, it can be observed to contract. How do you explain these phenomena

Amplitude is a measure of a waves a; speed b; distance c; energy d; frequency

A0.580-kg rock is tied to the end of a string and is swung in a circle with a radius of 0.500 meters. the velocity of the rock is 4.50 m/s. what is the centripetal force acting on the rock? 15.5 n 5.22 n 69.8 n 23.5 n

Carbon is allowed to diffuse through a steel plate 15 mm thick. the concentrations of carbon at the two faces are 0.65 and 0.30 kg c/m^3 fe, which are maintained constant. if the preexponential and activation energy are 6.2 x 10-7 m2 /s and 80,000 j/mol, respectively, compute the temperature at which the diffusion flux is 1.43 x 10^-9 kg/m^2 -s.