Please help! I need an answer for my exam and I can’t find it anywhere. A tuning fork is struck and is vibrating at a single frequency. If a second tuning fork with the same frequency is placed near the first it begins to vibrate. This is an example of .

forced vibration
resonance
Doppler effect
beats

Two kilograms of air within a piston–cylinder assembly executes a carnot power cycle with maximum and minimum temperatures of 800 k and 300 k, respectively. the heat transfer to the air during the isothermal expansion is 60 kj. at the end of the isothermal expansion the volume is 0.4 m3. assume the ideal gas model for the air. determine the thermal efficiency, the volume at the beginning of the isothermal expansion, in m3, and the work during the adiabatic expansion, in kj.