1) 0N... friction opposes the motion of an object, since the block is at rest there is no motion thus no friction
2) F=ma
= (5.5kg)(30m/s)
=165 N
Complete Question
The compete question is shown on the first uploaded question
Answer:
The speed is
Explanation:
From the question we are told that
The distance of separation is d = 4.00 m
The distance of the listener to the center between the speakers is I = 5.00 m
The change in the distance of the speaker is by 
The frequency of both speakers is 
Generally the distance of the listener to the first speaker is mathematically represented as
![L_1 = \sqrt{l^2 + [\frac{d}{2} ]^2}](https://tex.z-dn.net/?f=L_1%20%20%3D%20%20%5Csqrt%7Bl%5E2%20%2B%20%5B%5Cfrac%7Bd%7D%7B2%7D%20%5D%5E2%7D)
![L_1 = \sqrt{5^2 + [\frac{4}{2} ]^2}](https://tex.z-dn.net/?f=L_1%20%20%3D%20%20%5Csqrt%7B5%5E2%20%2B%20%5B%5Cfrac%7B4%7D%7B2%7D%20%5D%5E2%7D)

Generally the distance of the listener to second speaker at its new position is
![L_2 = \sqrt{l^2 + [\frac{d}{2} ]^2 + k}](https://tex.z-dn.net/?f=L_2%20%20%3D%20%20%5Csqrt%7Bl%5E2%20%2B%20%5B%5Cfrac%7Bd%7D%7B2%7D%20%5D%5E2%20%2B%20k%7D)
![L_2 = \sqrt{5^2 + [\frac{4}{2} ]^2 + 0.6}](https://tex.z-dn.net/?f=L_2%20%20%3D%20%20%5Csqrt%7B5%5E2%20%2B%20%5B%5Cfrac%7B4%7D%7B2%7D%20%5D%5E2%20%2B%200.6%7D)
Generally the path difference between the speakers is mathematically represented as

Here
is the wavelength which is mathematically represented as

=> 
=>
=>
Here n is the order of the maxima with value of n = 1 this because we are considering two adjacent waves
=>
=>
Isotope means that a chemical element that has the same number of protons but neutron number differs.
<u>Explanation:</u>
In isotope, the chemical element differs in neutron and nucleon number. Thus, different isotopes of a single component hold the same place in the periodic table.
Within the atom’s nucleus, protons are defined as an atomic number that is significantly equal to electrons in a neutral atom. An isotope of a given element has a different mass number. In general, every atomic number has a specific element, but in isotope, an atom may have a wide range of neutrons.
Answer:
Mike can travel 80 Km in 4 hours
Answer with Explanation:
We are given that
Weight of an ore sample=17.5 N
Tension in the cord=11.2 N
We have to find the total volume and the density of the sample.
We know that
Tension, T=
=buoyancy force
T=Tension force
W=Weight
By using the formula

N

Where
=Volume of object
=Density of water
=Acceleration due to gravity
Substitute the values then we get


Volume of sample=
Density of sample,
Where mass of ore sample=1.79 kg
Substitute the values then, we get

Density of the sample=