Answer:
fr = 269.3 N
Explanation:
Let's use Newton's second law, for this it is good to see the attached diagram,
X axis
fr -F2 = 0
fr = F2
Y Axis
N-W = 0
We must include the rotation balance, place the rotation point at the bottom of the ladder and take the positive counterclockwise turns.
Σ τ = 0
F2 x -W y / 2 = 0
We look for x and y with trigonometry
sin 70 = y / L
cos 70 = x / L
y = L sin70
x = L cos 70
We substitute and calculate F2
F2 L cos 70 = W L sin 70 / 2
F2 = mg/2 tan 70
F2 = 20 9.8/2 tan 70
F2 = 269.3 N
From the first equation (x axis)
fr = F2
fr = 269.3 N
Answer:
binding energy is 99771 J/mol
Exlanation:
given data
threshold frequency = 2.50 × Hz
solution
we get here binding energy using threshold frequency of the metal that is express as
..................1
here E is the energy of electron per atom and h is plank constant i.e. and x is binding energy
and here N is the Avogadro constant =
so E will
E =
so put value in equation 1 we get
= 2.50 × ×
solve it we get
x = 99770.99
so binding energy is 99771 J/mol
The answer is visible light. Most of the solar radiation that reaches the Earth is made up of visible and infrared light. Only a small amount of ultraviolet radiation reaches the surface of the earth. Ordinary sunlight or solar radiation is broken into visible light (0.4 nm - 0.8 nm), ultraviolet light ( 0.4 nm) and the infrared radiation (0.8 nm). The visible light makes up almost half of the total radiation reaching the surface of the Earth.
The normal force acting on the object is 500 N in the upward direction
<u>Explanation:</u>
As George is applying a downward force, the normal force will be in the upward direction. The normal force will be exerted due to the acceleration due to gravity exerted on the object.
So, as per Newton's second law, the normal force acting on the object can be measured by the product of mass of the object and the acceleration due to gravity acting on the object.
But as the acceleration due to gravity is a downward acting acceleration and the normal force is a upward acting force, so the acceleration will be having a negative sign in the formula.
Here, acceleration due to gravity g = -10 m/s² and mass is given as 50 kg, then
Normal force = 50 × (-10) = -500 N
So, the normal force acting on the object is 500 N in the upward direction.