it helps use less weight to pick up things and makes it way easier to work
Answer:
Concrete
Explanation:
The speed at which sound propagates is medium dependent. As one of the forms of mechanical waves, sound requires a material medium for propagation from place to place.
- Sound travels with the least speed in air because air particles are far apart and they are randomized.
- Sound travels with the greatest speed in solids. Concrete is the only solid material given in the choice.
The speed of sound increases from air to liquid and to solid.
imagine something setting stil, such as a box, since it is not moving, it has static friction
Light is refracted when it crosses the interface from air into glass in which it moves more slowly. Since the light speed changes at the interface, the wavelength of the light must change, also. The wavelength decreases as the light enters the medium and the light wave changes direction.
Answer:
a) flow must be doubled
, b) Ф₂ =∛2² Ф₀, c) Ф does not change
, d) flow is constant
, e) flow is constant
Explanation:
For this exercise let's use Gauss's law, which states that the flow is equal to the waxed load divided by the permissiveness of the vacuum
Ф = E. dA =
/ ε₀
Let's apply this equation
a) if the charge inside the Gaussian surface is doubled by the equation the flow must be doubled
Ф₀ =
/ ε₀
Ф₂ = 2
/ ε₀ = 2 Ф₀
b) the volume is V₂ = 2V₀. Area is the volume divided by the length
V = LLL = L³
A = LL = L²
A = V / L
V₂ = 2V₀
L³ = 2 L₀³
L = ∛2 L₀
V₂ = A₂ L
A₂ = V₂ / L
A₂ = 2V₀ / L = 2 L₀³ / (∛2 L₀)
A₂ = 2 /∛2 V₀ / L₀
A₂ = ∛2² A₀
Ф₀ = E A₀
Ф₂ = E A₂
Ф₂ = E ∛2² A₀
Ф₂ =∛2² Ф₀
The flow doubles when the volume is increased by the factor 
c) the flow does not depend on the shape of the surface, so Ф does not change
d) the flow does not depend on the position of the load, while inside the surface the flow is constant
e) when the load leaves the surface, the load inside drops to ero, so the flow changes to zero
Ф = 0