The acceleration of the first block (4 kg) is -9.8 m/s².
The given parameters:
- <em>Mass of the first block, m₁ = 4.0 kg</em>
- <em>Mass of the second block, m₂ = 2.0 kg</em>
The net force on the system of the two blocks is calculated as follows;

where;
- <em>T </em><em>is the tension in the connecting string due weight of the first block</em>

Thus, the acceleration of the first block (4 kg) is -9.8 m/s².
Learn more about net force on two connected blocks here: brainly.com/question/13539944
Answer:
B
Explanation:
it's converts electrical energy to mechanical energy.
Answer:
Time period between the successive beats will be 0.1703 sec
Explanation:
We have given speed of the sound v = 349 m/sec
Wavelength of piano 
Wavelength of piano 
So frequency of piano A 
Frequency of piano B 
So beat frequency f = 455.61 - 449.74 = 5.87 Hz
So time period 
So time period between the successive beats will be 0.1703 sec