Answer:
y = 80.2 mille
Explanation:
The minimum size of an object that can be seen is determined by the diffraction phenomenon, if we use the Rayleigh criterion that establishes that two objects can be distinguished without the maximum diffraction of a body coincides with the minimum of the other body, therefore so much for the pupil of the eye that it is a circular opening
θ = 1.22 λ/ d
in a normal eye the diameter of the pupils of d = 2 mm = 0.002 m, suppose the wavelength of maximum sensitivity of the eye λ = 550 nm = 550 10⁻⁹ m
θ = 1.22 550 10⁻⁹ / 0.002
θ = 3.355 10⁻⁴ rad
Let's use trigonometry to find the distance supported by this angle, the distance from the moon to the Earth is L = 238900 mille = 2.38900 10⁵ mi
tan θ = y / L
y = L tan θ
y = 2,389 10⁵ tan 3,355 10⁻⁴
y = 8.02 10¹ mi
y = 80.2 mille
This is the smallest size of an object seen directly by the eye
Plugging in for the Earth's mass and for G, we have 11.2 km/s for the escape velocity for an object launched from the Earth's surface. This is about 25,000 miles per hour
Answer: 31.33 degrees
Explanation:
The diffraction angles 
when we have a slit divided into 
parts are obtained by the following equation:
(1)
Where:
is the width of the slit
is the wavelength of the light
is an integer different from zero.
Now, the first-order diffraction angle is given when 
, hence equation (1) becomes:
(2)
Now we have to find the value of 
:
(3)
We know:
In addition we are told the diffraction grating has 5000 slits per mm, this means:
Substituting the known values in (3):
<u>Finally:</u>
>>>This is the first-order diffraction angle
1. Tangential velocity:
<em>e) the instantaneous velocity of a body moving in a circular path.</em>
2. Parabolic pathway
<em>c. a curved path followed by projectiles</em>
3. Projectile
<em>d) an object projected through space, traveling in two dimensions, that accelerates vertically due to gravity.</em>
4. Centripetal acceleration
<em>a) acceleration towards the center caused by the centripetal force</em>
5. Centripetal force
<em>b) a force which keeps a body moving with a uniform speed along a circular path and is directed along the radius towards the center</em>
The train travells at he speed of 225 km/2.5h
now
225km=225000m
2.5 hr=150min=9000s
=>avg sp of train is=225000/9000s=25m/s
