Answer:
The value of speed of wooden block at the instant after the collision
262.41 
Explanation:
Given data
Mass of block = 6.3 kg
Mass of bullet = 0.086 kg
Velocity of bullet
= 266 
Final velocity of whole system is

Put all the values in above formula we get

262.41 
This is the value of speed of wooden block at the instant after the collision.
Answer:
a) t=24s
b) number of oscillations= 11
Explanation:
In case of a damped simple harmonic oscillator the equation of motion is
m(d²x/dt²)+b(dx/dt)+kx=0
Therefore on solving the above differential equation we get,
x(t)=A₀
where A(t)=A₀
A₀ is the amplitude at t=0 and
is the angular frequency of damped SHM, which is given by,

Now coming to the problem,
Given: m=1.2 kg
k=9.8 N/m
b=210 g/s= 0.21 kg/s
A₀=13 cm
a) A(t)=A₀/8
⇒A₀
=A₀/8
⇒
applying logarithm on both sides
⇒
⇒
substituting the values

b) 

, where
is time period of damped SHM
⇒
let
be number of oscillations made
then, 
⇒
The bonds that hold atoms together to form molecules are called covalent bonds. They are pretty tough and not easily made or broken apart. It takes energy to make the bonds and energy is released when the bonds are broken.
Answer:
Aphelion: 6404 W/m2
Perihelion: 14978 W/m2
Explanation:
The solar energy flux depends on the solar power output divided by the surface of a sphere with a radius equal to the distance to the Sun.

The distances we need are the aphelion and perihelion of Mercury.
Planetary orbits are ellipses. In an ellipse the eccentricity is related to linear eccentricity and the length of the semi major axis:

Where
e: eccentricity
c: linear eccentricity
a: semi major axis
The linear eccentricity is equal to the distance of the focus of the center of the ellipse.

a = 0.39 AU = 5.83e10 m

In planetary orbits the Sun is in one of the fucuses. With this we can calculate the prihelion and aphelion as:
Ap = a + c = 5.83e10 + 1.22e10 = 7.05e10 m
Pe = a - c = 5.83e10 - 1.22e10 = 4.61e10 m
And the solar energy fluxes will be:


<h2>
Answer: an underground lake</h2>
Explanation:
In general, sound (mechanical waves) travels faster in solids than in liquids, and faster in liquids than in gases. This is because <u>the speed of the mechanical waves is determined by a relationship between the elastic properties of the medium </u>in which they are propagated and the mass per unit volume of the medium (that is:<u>density</u>).
In other words: The speed of sound varies depending on the medium through which the sound waves travel.
So, if we are told the sound wave initially had a speed of 4,000 m/s and it suddenly decreases to 1,500 m/s, this means the sound waves passed from a solid medium to a liquid medium.
Hence, the correct option is: an underground lake.