PHYSICS HIGH SCHOOL

Consider a portion of a cell membrane that has a thickness of 7.50 nm and 1.4 µm ✕ 1.4 µm in area. A measurement of the potential difference across the inner and outer surfaces of the membrane gives a reading of 86.0 mV.a) Determine the amount of current that flows through this portion of the membrane
b) By what factor does the current change if the side dimensions of the membrane portion is halved? The other values do no change
increase by factor of 2
decrease by factor of 8
decrease by factor of 2
decrease by a factor of 4
increase by factor of 4

Answers

Answer 1

Answer:

Answer:

Part a: The current is 1.49x10⁻¹² A

Part b: The current is decreased by a factor of 4.

Explanation:

Part a

The area is given as

A =(1.4*10⁻⁶)² =1.96*10⁻¹² m²

The resistance is given as where resistivity of the membrane material is 1.30 x 10⁷ ohms*m

R=pL/A =(1.3*10⁷)(7.5*10⁻⁹)/(1.96*10⁻¹²)

R=4.97x10¹⁰ ohms

So the resistance is 4.97x10¹⁰ ohms.

I=V/R =86.0x10⁻³/5.77x10¹⁰

I=1.49x10^⁻¹² A

So the current is 1.49x10⁻¹² A

S=So/2=1.4/2 =0.7μm

A=(0.7*10^-6)^2=4.9*10⁻¹³ m²

R=pL/A =(1.3*10⁷)(7.5*10⁻⁹)/(4.9*10⁻¹³)

R=1.98x10¹¹ ohms

So the resistance is 1.98x10¹¹ ohms.

I=V/R =86.0x10⁻³/1.98x10¹¹

I2=4.52x10^⁻¹³ A

So the ratio of the new current vs the old current is as

I2/I=4.52x10^⁻¹³/1.49x10⁻¹²=0.25

So the current is decreased by a factor of 4.

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a lump of putty and a rubber ball have equal mass. both are thrown with equal speed against a wall. the putty sticks to the wall. the ball bounces back at nearly the same speed with which it hit the wall. which object experiences the greater momentum change?

Answers

The bouncy ball experiences the greater momentum change.

To understand why, you need to remember that momentum is actually
a vector quantity ... it has a size AND it has a direction too.

The putty and the ball have the same mass, and you throw them
with the same speed. So, on the way from your hand to the wall,
they both have the same momentum.
Call it " M in the direction toward the wall ".

After they both hit the wall:

-- The putty has zero momentum.
Its momentum changed by an amount of M .

-- The ball has momentum of " M in the direction away from the wall ".
Its momentum changed by an amount of 2M .

Rubber ball will experience the greater momentum change than the lump of putty

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Further explanation

Newton's second law of motion states that the resultant force applied to an object is directly proportional to the mass and acceleration of the object.

$\large {\boxed {F = ma }$

F = Force ( Newton )

m = Object's Mass ( kg )

a = Acceleration ( m )

Let us now tackle the problem !

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Given:

mass of a lump of putty = m

mass of rubber ball = m

initial speed of putty = v

final speed of putty = 0

initial speed of rubber ball = v

final speed of rubber ball = -v

Asked:

the change in momentum = Δp = ?

Solution:

Lump of Putty :

$\Delta p_(putty) = mv_f' - mv_i$

$\Delta p_(putty) = m(0) - mv$

$\Delta p_(putty) = - mv$

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Rubber Ball:

$\Delta p_(ball) = mv_f' - mv_i$

$\Delta p_(ball) = m(-v) - mv$

$\Delta p_(ball) = - 2mv$

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$\Delta p_(ball) : \Delta p_(putty) = - 2mv : - mv$

$\Delta p_(ball) : \Delta p_(putty) = 2 : 1$

$\Delta p_(ball) = 2\Delta p_(putty)$

$\Delta p_(ball) > \Delta p_(putty)$

From calculation above , we can conclude that rubber ball will experience the greater momentum change than the lump of putty

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Learn more

Impacts of Gravity : brainly.com/question/5330244
Effect of Earth’s Gravity on Objects : brainly.com/question/8844454
The Acceleration Due To Gravity : brainly.com/question/4189441
Newton's Law of Motion: brainly.com/question/10431582
Example of Newton's Law: brainly.com/question/498822

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Answer details

Grade: High School

Subject: Physics

Chapter: Dynamics

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Keywords: Gravity , Unit , Magnitude , Attraction , Distance , Mass , Newton , Law , Gravitational , Constant

If people from Georgia have just experienced an extremely cold winter the last couple of months, what would the climate most likely be classified as? Polar
Temperate
Maritime
Tropical

Answers

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Answer:

polar

Explanation:

they said it was extreme so atleast it would be polar

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Answers

Answer:

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In a physics experiment, two equal-mass carts roll towards each other on a level, low-friction track. One cart rolls rightward at 2 m/s and the other cart rolls leftward at 1 m/s. After the carts collide, they couple (attach together) and roll together with a speed of __________. Ignore resistive forces.a. 0.5 m/sb. 0.33 m/s
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d. 1.0 m/s
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Answers

Answer:

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Explanation:

Conservation of momentum :

$m_1u_1+m_2u_2=m_1v_1+m_1v_2$

Where :

$m_1, m_2$ = masses of object collided

$u_1,u_2$ = initial velocity before collision

$v_1,v_2$ = final velocity after collision

We have :

Two equal-mass carts roll towards each other.

$m_1=m_2=M$

Initial velocity of $m_1=u_1=2 m/s$

Initial velocity of $m_2=u_2=-1 m/s$ (opposite direction)

Final velocity of $m_1=v_1=v$ (same direction )

Final velocity of $m_2=v_2=v$ (same direction)

$M* 2 m/s+M(-1 m/s)=Mv+Mv$

$1 m/s=2v$

v = 0.5 m/s

rg135

The speed of the carts after their collision is 0.5 m/s.

red giant white dwarf black hole supernova a shock wave produced by extremely high temperatures a low-mass star that has shed its outer layers a star whose outer shell has a high-mass star that has collapsed from gravity expanded and cooled

Answers

Answer:

Asymptotic-giant-branch stars have helium-burning shells inside the hydrogen-burning shells, whereas red-giant-branch stars have hydrogen-burning shells only. In either case, the accelerated fusion in the hydrogen-containing layer immediately over the core causes the star to expand.

Charged objects have a _________ charge. A. net B. moving C. positive D. negative

Answers

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