C is what i would go with
Frequency = (speed) / (wavelength)
Frequency = (331 m/s) / (0.6 m) = 551.7 Hz
90 km/h is 25 m/s
the relative velocity when cars are traveling in opposite directions is the sum of the two
25+20= 45 m/s
The answer is A
Materials that are good conductors of thermal energy are called thermal conductors. Metals are very good thermal conductors. Materials that are poor conductors of thermal energy are called thermal insulators. Gases such as air and materials such as plastic and wood are thermal insulators
Explanation:
They will repel, meaning that they are made of an electrical conductor.
