Friction occurs when two surfaces come into contact. Excess friction hinders movement, and it wastes energy. Friction refers to a force that opposes motion. It is important because it is applied in almost all life processes.
Its to protect the cell from its surroundings, its selectively permeable to ions and organic molecules
C. Tripling the length and reducing the radius by a factor of 2 is the change to a pipe would increase the conductance by a factor of 12.
<u>Explanation:</u>
As we know that the resistance is directly proportional to the length of the pipe and it is inversely proportional to the cross sectional area of the pipe.
So it is represented as,
R∝ l /A [ area is radius square]
So k is the proportionality constant used.
R = kl/A
Conductance is the inverse of resistance, so it is given as,
C= 1/R.
R₁ = kl₁ / A₁
R₂ = kl₂/A₂
R₂/R₁ = 1/12 [∵ conductance is the inverse of resistance]
= l₂A₁ / l₁A₂
If we chose l₁/l₂= 3 and A₂/A₁= 4 So R₂/R₁= 1/3×4 = 1/12
So tripling the length and reducing the radius by a factor of 2 would increase the conductance by a factor of 12.
Answer:
- blue-black PHYSICAL PROPERTY
- crystalline PHYSICAL PROPERTY
- solid PHYSICAL PROPERTY
- sublimes to a violet-colored gas PHYSICAL PROPERTY
- reacts with aluminum and many other metals CHEMICAL PROPERTY
Explanation:
Chemical properties are visible through chemical reactions, in which the chemical identity changes to form new substances. On the other hand, physical properties are evident without a change in the identity of a substance.
<em />
<em>Which of these five properties are physical and which are chemical?</em>
- blue-black PHYSICAL PROPERTY
- crystalline PHYSICAL PROPERTY
- solid PHYSICAL PROPERTY
- sublimes to a violet-colored gas PHYSICAL PROPERTY
- reacts with aluminum and many other metals CHEMICAL PROPERTY
2 is the correct answer because with 2O2 molecules it balances the chemical equation.
Hope that helps