Answer:
73 db
Explanation:
A single air conditioner is equivalent to 70 dB frequency. An extra air conditioning unit would therefore double the sound frequency. It does not, however, double the decibels to 140 dB. Instead, it adds only 3 dB to the 70 dB, making the total decibels of two air conditioning units equal to 73 db
Hence the correct option is b that is 73 db
Answer:

Explanation:
Given:
- spring constant of the spring attached to the input piston,

- mass subjected to the output plunger,

<u>Now, the force due to the mass:</u>



<u>Compression in Spring:</u>



or

The two letters are B and A, in that order.
D. a and c
Explanation:
To make a generator out of a bicycle, Devon will need two magnets and coil of wire.
There is a close knit relationship between magnetism and electricity. Electricity can be generated by a wire changing flux in the presence of a magnetic field.
- The magnets provide magnetic field for the process.
- The coil of wire is placed in between the magnetic field generated by the magnets.
- The bicycle pedal is connected to the set up to turn the wire in between the magnetic fields.
- This way, electricity is produced.
Learn more:
Electromagnet brainly.com/question/2191993
#learnwithBrainly