SPH4U | Physics 12 11. Explain each of the following: [C 2] (a) A spring which has an extension of "x" stores energy "E". How much energy stored in it if the is extension is "2x". ( b ) How do the strings in a tennis racquet behave like a spring? 12. Explain why we can hear sounds around corners, but we cannot see around corners, even though sound and light both travel as waves [C 2] 13. You are in a sealed room with no windows or doors. [C 3] (a) State the two postulates of the special theory of relativity (a) You are asked whether the room is at rest or moving with a constant velocity. Are there any experiments that you could do to allow you to answer the question? Explain your reasoning (b) You are asked whether the room is an inertial frame of reference or a non-inertial FOR. Are there any experiments that you could do to allow you to answer the question? Explain your reasoning. 2 F