Assuming the accleration applied was constant, we have



Then the force applied to the ball is given by


To solve this problem it is necessary to apply the concepts related to wavelength depending on the frequency and speed. Mathematically, the wavelength can be expressed as

Where,
v = Velocity
f = Frequency,
Our values are given as
L = 3.6m
v= 192m/s
f= 320Hz
Replacing we have that


The total number of 'wavelengths' that will be in the string will be subject to the total length over the size of each of these undulations, that is,



Therefore the number of wavelengths of the wave fit on the string is 6.
Here we have mass that moves at ceratin speed. This means that we have momentum. The law that must be observed is law of conservation of momentum. It states that momentum before certain event is equal to a momentum after that event. Here we have three masses so we can write this as:

Before the firecracker blows a coconut does not move, so left side is equal to 0:

We know that m1=m2=m and m3=2m. Also we are asked to find v3f so we can rewrite formula:

We must take in consideration that two parts with same mass do not move in same direction. The center of mass of these two parts moves between them at angle of 45° with respect to both south and west. The speed of a center of mass is:

This speed we can insert into formula for v3f:

We can see that part of a coconut with biggest mass has same speed as center of mass of two other parts. Negative sign shows that direction is opposite to direction of two pats. Biggest part moves towards north-east.
Answer:
1. the voltage will be 2.35×12.5 = 29.4V
2. the resistance would be 9.0/6.2= 1.45ohms
3. in series they will add up thus 4+8+12= 24ohms
4. in parallel it will be 2.18ohms