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3 years ago

Describe how cell membranes are selectively permeable

1 answer:

5 0

<span>Cell membranes are selectively permeable because it allows some things to enter or leave the cell while keeping other things outside or inside the cell.</span>

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What is gravitational force

Salsk061 [2.6K]

Gravitational forces are forces of attraction. It's like the Earth pulling on you and keeping you on the ground.

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4 years ago

Read 2 more answers

As an intern with an engineering firm, you are asked to measure the moment of inertia of a large wheel, for rotation about an ax

AysviL [449]

Answer:

$I=2.766\ kg.m^2$

Explanation:

We have:

diameter of the wheel, $d=0.88\ m$

weight of the wheel, $w_w=280\ N$

mass of hanging object to the wheel, $m_o=6.32\ kg$

speed of the hanging mass after the descend, $v_o=4\ m.s^{-1}$

height of descend, $h=2.5\ m$

(a)

moment of inertia of wheel about its central axis:

$I=\frac{1}{2} m.r^2$

$I=\frac{1}{2} \frac{w_w}{g}.r^2$

$I=\frac{1}{2} \times \frac{280}{9.8}\times 0.44^2$

$I=2.766\ kg.m^2$

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3 years ago

a person dives off the edge of aa cliff 33m above the surface of the sea. assuming that air resistance is negligible, how long d

USPshnik [31]

Answer:

The time is $t = 2.595 \ s$

The speed is $v = 25.43 \ m/s$

Explanation:

From the question we are told that

The height of the cliff is $h = 33 \ m$

Generally from kinematic equation we have that

$h = ut + \frac{1}{2} gt^2$

before the jump the persons initial velocity is u = 0 m/s

$33 = 0 * t + \frac{1}{2} 9.8 * t^2$

=> $t = 2.595 \ s$

Generally from kinematic equation

$v= u + gt$

=> $v= 0 + 9.8 * 2.595$

=> $v = 25.43 \ m/s$

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3 years ago

What's the difference between Uniform magnetic field and Non-uniform magnetic field?

Galina-37 [17]

Magnetic field is the magnetic effect of electric currents and magnetic materials. The magnetic field at any given point specified by both direction and a magnitude. So uniform magnetic field has equal amount of force or magnetic force in both side of the object while the non uniform magnetic field has one of the object exert more than the other

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3 years ago

Describe a positive and negative net force acting on an object

Artemon [7]

There are different forces acting on an object like nuclear force , gravitational force...plus external forces like friction and other..

net sum of all these is resultnat

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3 years ago