<u>Answer:</u> The Fermi velocity of lead is 64.4 km/s.
<u>Explanation:</u>
To calculate the Fermi velocity, we use the equation:

where,
h = Planck's constant = 
= mass of electron = 
N = Number of atoms present in per volume of atom multiplied by number of electrons present in given atom = 
= Avogadro's number =
(When the mass is in kilograms)
V = Volume = 
M = molecular weight of lead = 207.2 g/mol
Putting values in above equation, we get:

(Conversion factor: 1 km = 1000 m)
Hence, the Fermi velocity of lead is 64.4 km/s
Answer:
u = 104.68 m/s
Explanation:
given,
horizontal distance = 150 m
elevation of 12.4 m
angle = 8.6°
horizontal motion = x = u cos θ. t .............(1)
vertical motion =
................(2)
from equation(1) and (2)
..........{3}




u = 104.68 m/s
The initial speed of the ball is u = 104.68 m/s
Answer:
I1 = 2/5 M1 R^2 for a sphere about its center
I2 = 2/5 M2 (2 R)^2 = 2/5 M2 R^ * 4 = 8/5 M2 R^2
Remember that M2 is greater than M1 by a factor 0f 2^3 = 8
Then I2 exceeds I1 by a factor of 32
Answer:
Height of tree = 78.35 meters.
Explanation:
We have
1 meter = 3.28 feet
That is

Here height of tree = 257 ft
Height of tree = 257 x 0.3048 = 78.35 m
Height of tree = 78.35 meters.