Answer:
The velocity of water at the bottom,
Given:
Height of water in the tank, h = 12.8 m
Gauge pressure of water,
Solution:
Now,
Atmospheric pressue,
At the top, the absolute pressure,
Now, the pressure at the bottom will be equal to the atmopheric pressure,
The velocity at the top, , l;et the bottom velocity, be .
Now, by Bernoulli's eqn:
where
Density of sea water,
Answer:
<h2><em>
12.45eV</em></h2>
Explanation:
Before calculating the work function, we must know the formula for calculating the kinetic energy of an electron. The kinetic energy of an electron is the taken as the difference between incident photon energy and work function of a metal.
Mathematically, KE = hf - Ф where;
h is the Planck constant
f is the frequency = c/λ
c is the speed of light
λ is the wavelength
Ф is the work function
The formula will become KE = hc/λ - Ф. Making the work function the subject of the formula we have;
Ф = hc/λ - KE
Ф = hc/λ - 1/2mv²
Given parameters
c = 3*10⁸m/s
λ = 97*10⁻⁹m
velocity of the electron v = 3.48*10⁵m/s
h = 6.62607015 × 10⁻³⁴
m is the mass of the electron = 9.10938356 × 10⁻³¹kg
Substituting the given parameters into the formula Ф = hc/λ - 1/2mv²
Ф = 6.63 × 10⁻³⁴*3*10⁸/97*10⁻⁹ - 1/2*9.11*10⁻³¹(3.48*10⁵)²
Ф = 0.205*10⁻¹⁷ - 4.555*10⁻³¹*12.1104*10¹⁰
Ф = 0.205*10⁻¹⁷ - 55.163*10⁻²¹
Ф = 0.205*10⁻¹⁷ - 0.0055.163*10⁻¹⁷
Ф = 0.1995*10⁻¹⁷Joules
Since 1eV = 1.60218*10⁻¹⁹J
x = 0.1995*10⁻¹⁷Joules
cross multiply
x = 0.1995*10⁻¹⁷/1.60218*10⁻¹⁹
x = 0.1245*10²
x = 12.45eV
<em>Hence the work function of the metal in eV is 12.45eV</em>
Answer:
2:1
Explanation:
It is given that,
The diameter of a white blood cell is 12 micrometers
The diameter of white blood cell according to a model is 24 micrometers.
We need to find the ratio of model size to actual size. It can be done as follows :
Hence, the ratio of model size to actual size is 2:1.
Answer:
Explanation:
Let the height of the tree is y and the distance of tree from point B is x.
According to the diagram
x = 0.55 y ..... (1)
(50 + 0.55y) 1.17 = y ..... from equation (1)
58.5 + 0.644 y = y
0.356 y = 58.5
y = 164.3 ft
Answer:
Part a)
U = 15.5 J
Part b)
h = 1.05 m
Part c)
v = 4.55 m/s
Explanation:
Part a)
Initial potential energy stored in the spring is given by
now we have
x = 20.0 cm
now from above formula we will have
Part b)
By mechanical energy conservation law we can say that initial spring potential energy stored = final gravitational potential energy at the top position
So maximum height from gun is 1.05 m
Part c)
For muzzle velocity of the ball we can use the energy conservation again
According to which the final kinetic energy of the ball = initial spring energy stored in it