Answer:
The force acting on the ball is 92.4 N.
Explanation:
Given that,
Initial speed of the ball, u = 0
Final speed of the ball, v = 31.6 m/s
The average power generated during the serve is 2920 W. Power generated by an object is given by :

W is the work done, W = Fd

Since, 
So,

F is the force acting on the ball

So, the force acting on the ball is 92.4 N. Hence, this is the required solution.
<h2>Answer: protons and neutrons.
</h2>
The atomic nuclei of almost all elements consist of protons and neutrons.
The nucleus of an atom has very small dimensions. However, it <u>occupies its central part and concentrates more than 99% of its total mass.
</u>
It is in the nucleus that the protons (positive charge) and neutrons (neutral charge) are found.
Answer:
Therefore, we need an invert, and a rectifier, along with the transformer to do the job.
Explanation:
A transformer, alone, can not be used to convert a DC voltage to another DC voltage. If we apply a DC voltage to the primary coil of the transformer, it will act as short circuit due to low resistance. It will cause overflow of current through winding, resulting in overheating pf the transformer.
Hence, the transformer only take AC voltage as an input, and converts it to another AC voltage. So, the output voltage of a transformer is also AC voltage.
So, in order to convert a 6 V DC to 1.5 V DC we need an inverter to convert 6 V DC to AC, then a step down transformer to convert it to 1.5 V AC, and finally a rectifier to convert 1.5 V AC to 1.5 V DC.
<u>Therefore, we need an invert, and a rectifier, along with the transformer to do the job.</u>