<span>Answer:
Let m = mass of cannon
Then
10000 = ma
a = 10000/m
v^2 = u^2 + 2as
v^2 = 0 + 2as
84^2 = 2(2.21)(10000/m)
84^2 m = 4.42(10000)
m = 6.264172336
= 6.26 kg
Part 2
Range = u^2sin(2x38)/g
= 84^2sin(76)/9.8
= 698.6129229
= 698.6 m</span>
Answer: B. Concrete
Explanation:
Let N = reacting force pressing the bodies in context together (units in Newtons),
The question stated that the force pressing the two mounted/stacked objects together is equal to the weight of the object on top.
We need to start by finding the weight of the piece of wood.
friction is given by
f = μN
The value of f is 22.5,
and from the chart reference the coefficient of friction between wood and stone, μ is 0.30.
22.5 = 75. 0.30
Putting the values into the equation: 22.5 = 0.30N.
Divide both sides by 0.30 to find the value of N:
N= 22.5/0.3 = 75
Now that the piece of wood will be placed on another surface, its weight of 75 Newton is the force pressing the two bodies together.
To determine the new surface, you should find the new coefficient of friction by using the new value of the force of friction given 46.5:
46.5 = µ(75).
Divide both sides by 75 to isolate μ.
The refer chart also indicates that the coefficient of friction equals 0.62 between wood and concrete, so the new surface corresponding to 0.62 is the concrete, which is (B).
Answer: B. bending light
Explanation:
The phenomenom of vision in human eye is thanks to refraction (when light changes its direction as it passes through one medium to another), and this is what the cornea and the lens do.
When the ray of light encounters the eye, the first thing it finds is the <u>cornea</u>, which<u> bends this ray and begins to form an image</u>, then light passes through the <u>pupil</u>, which is in charge of regulating the amount of light that enters in the eye.
After light travels through pupil it passes through the <u>lens</u>, where <u>the rays of light change the direction again in order to focus the formed image on the retina.
</u>
At this point it is important to note the formed image is downward, then the retina transforms light into electrical impulses that are sent to the brain through the optic nerve and finally the brain interprets these messages, and forms a right upward image.
In the image attached these parts can be seen.
Answer:

Explanation:
= Change in frequency = 2.1 Hz
= Frequency of source of sound = 440 Hz
= Maximum of the microphone
= Speed of sound = 343 m/s
= Time period = 2 s
We have the relation

Amplitude is given by

The amplitude of the simple harmonic motion is
.
The atom becomes positively charged.
EXPLANATION :
When all the electrons are removed from the atom, the atom contains only protons and neutrons. The neutron is a neutral nucleon. ...
Hence, the correct answer is that atom will be positively charged.