If you shout at a cliff wall that is 440 m away and the air temperature is at 25 °C, how long will it take before you hear your echo?

According to the law of conservation of mass, in a chemical reaction the total starting mass of all the reactants equal the total final mass of all the products. true or false?

Quantum mechanics applies to subatomic, atomic, nanometer-size, and micrometer-size systems. nanometer, micrometer, and kilometer-size systems. atomic, nanometer-size, and micrometer-size systems. subatomic, atomic, and nanometer-size systems.

You have a resistor and a capacitor of unknown values. first, you charge the capacitor and discharge it through the resistor. by monitoring the capacitor voltage on an oscilloscope, you see that the voltage decays to half its initial value in 2.70 miss . you then use the resistor and capacitor to make a low-pass filter. what is the crossover frequency fc?