Answer:
The gravitational potential energy of a system is -3/2 (GmE)(m)/RE
Explanation:
Given
mE = Mass of Earth
RE = Radius of Earth
G = Gravitational Constant
Let p = The mass density of the earth is
p = M/(4/3πRE³)
p = 3M/4πRE³
Taking for instance,a very thin spherical shell in the earth;
Let r = radius
dr = thickness
Its volume is given by;
dV = 4πr²dr
Since mass = density* volume;
It's mass would be
dm = p * 4πr²dr
The gravitational potential at the center due would equal;
dV = -Gdm/r
Substitute (p * 4πr²dr) for dm
dV = -G(p * 4πr²dr)/r
dV = -G(p * 4πrdr)
The gravitational potential at the center of the earth would equal;
V = ∫dV
V = ∫ -G(p * 4πrdr) {RE,0}
V = -4πGp∫rdr {RE,0}
V = -4πGp (r²/2) {RE,0}
V = -4πGp{RE²/2)
V = -4Gπ * 3M/4πRE³ * RE²/2
V = -3/2 GmE/RE
The gravitational potential energy of the system of the earth and the brick at the center equals
U = Vm
U = -3/2 GmE/RE * m
U = -3/2 (GmE)(m)/RE
Answer:
PART A: option b. .43nm
PART B: option d. 0.11nm
PART C: option c. The wavelengths of visible light are too long compared to the atomic spacing.
Explanation:
Given data
Wavelength λ = 0.20 nm
Angle θ = 0.8 rad
(a)
wavelength of x-ray to give maximum at the same location
λ₂ = m λ
Here, m = 2 is the interference fringe order.
Substitute the values in the above equation.
λ₂ = 2 × 0.2
= 0.4 nm
Hence, the wavelength of x-ray to give maximum at the same location is 0.4nm
(b)
The crystal plane separation is equal to d
The value of θ is equal to 0.8 rad.
Convert rad into degree as follows:
0.8 rad =
= 144°/π = 45.86°
Solve for d, using equation (1) as follows:
2dsinθ = mλ
d = mλ / 2sinθ
d = (1) 0.17 / 2Sin45.86°
d = 0.17 / 1.9065
d = 0.089 nm
(c)
The visible light can not be used to study the structure of proteins because of the high wavelength of the visible light.
Answer:
Explanation:
Given
coefficient of kinetic friction
=0.34
inclination 
weight of block=51 N
(a) When block is moving upward friction force acts downward
thus

as block is moving with constant velocity thus
is zero



(b)When Block slides down the wall friction changes its direction to oppose the block




Answer:
Copper is the best conductor