Answer: The plasma membrane is called a selectively permeable membrane as it permits the movement of only certain molecules in and out of the cells. Not all molecules are free to diffuse. If plasma membrane ruptures or breaks down then molecules of some substances will freely move in and out of the cells. Semipermeable membrane describes a membrane that allows some particles to pass through (by size), whereas the selectively permeable membrane "chooses" what passes through (size is not a factor). Selective permeability is a property of cellular membranes that only allows certain molecules to enter or exit the cell. This is important for the cell to maintain its internal order irrespective of the changes to the environment. For example, water, ions, glucose and carbon dioxide may need to be imported or exported from the cell depending on its metabolic activity. Similarly, signaling molecules may need to enter the cell and proteins may need to be released into the extracellular matrix. The presence of a selectively permeable membrane allows the cell to exercise control over the quantum, timing and rate of movement of these molecules.
Explanation: hope this helps you with your work/assingment! Have a wonderful day/night!
Answer:
Net force.
Explanation:
All of the forces acting on an object combine to create a net force.
The simplest device to accomplish that process is a transformer.
Answer:
4 kg → +4 m/s
5 kg → -5 m/s
Explanation:
The law of conservation of momentum states that:
- m₁v₁ + m₂v₂ = m₁v₁' + m₂v₂'
- left side → velocities before collision
- right side → velocities after collision
You'll notice that we have two missing variables: v₁' & v₂'. Assuming this is a perfectly elastic collision, we can use the conservation of kinetic energy to set the initial and final velocities of the individual bodies equal to each other.
Let's substitute all known variables into the first equation.
- (4)(-6) + (5)(3) = (4)v₁' + (5)v₂'
- -24 + 15 = 4v₁' + 5v₂'
- -9 = 4v₁' + 5v₂'
Let's substitute the known variables into the second equation.
- (-6) + v₁' = (3) + v₂'
- -9 = -v₁' + v₂'
- 9 = v₁' - v₂'
Now we have a system of equations where we can solve for v₁ and v₂.
- -9 = 4v₁' + 5v₂'
- 9 = v₁' - v₂'
Use the elimination method and multiply the bottom equation by -4.
- -9 = 4v₁' + 5v₂'
- -36 = -4v₁' + 4v₂'
Add the equations together.
<u>The final velocity of the second body (5 kg) is -5 m/s</u>. Substitute this value into one of the equations in the system to find v₁.
- 9 = v₁' - v₂'
- 9 = v₁' - (-5)
- 9 = v₁' + 5
- 4 = v₁'
<u>The final velocity of the first body (4 kg) is 4 m/s.</u>
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We can verify our answer by making sure that the law of conservation of momentum is followed.
- m₁v₁ + m₂v₂ = m₁v₁' + m₂v₂'
- (4)(-6) + (5)(3) = (4)(4) + (5)(-5)
- -24 + 15 = 16 - 25
- -9 = -9
The combined momentum of the bodies before the collision is equal to the combined momentum of the bodies after the collision. [✓]
Answer:
conduction
Explanation:
Conduction transfers heat via direct molecular collision. An area of greater kinetic energy will transfer thermal energy to an area with lower kinetic energy. Higher-speed particles will collide with slower speed particles.