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3 years ago

Why are potassium molecules likely to enter a red blood cell?

1 answer:

5 0

they have to be selective permeable to filter out the waste products but allow the nutrients and blood cells to pass through.

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Suppose an object’s initial velocity is 10 m/s and its final velocity is 4 m/s. Mass is constant.

Ostrovityanka [42]

The correct answer is:

Work is negative, the environment did work on the object, and the energy of the system decreases.

In fact, the work-energy theorem states that the work done by the system is equal to its variation of kinetic energy:

$W=\Delta K=K_f -K_i$

In this problem, the variation of kinetic energy $\Delta K$ is negative (because the final velocity is less than the initial velocity), so the work is negative, and this means that the environment did work on the object, and its energy decreased.

3 0

3 years ago

Read 2 more answers

A man 2 m tall walks horizontally at a constant rate of 1 m/s toward the base of a tower 23 m tall. When the man is 10 m from th

Evgen [1.6K]

Answer:

$\dfrac{d\theta}{dt}=0.038\ rad/s$

Explanation:

Given that

$\dfrac{dx}{dt}= -1\ m/s$

From the diagram

$tan\theta=\dfrac{21}{x}$

By differentiating with time t

$sec^2\theta \dfrac{d\theta}{dt}=-\dfrac{21}{x^2}\dfrac{dx}{dt}$

When x= 10 m

$tan\theta=\dfrac{21}{10}$

θ = 64.53°

Now by putting the value in equation

$sec^2\theta \dfrac{d\theta}{dt}=-\dfrac{21}{x^2}\dfrac{dx}{dt}$

$sec^264.53^{\circ} \dfrac{d\theta}{dt}=-\dfrac{21}{10^2}\times (-1)$

$\dfrac{d\theta}{dt}=0.038\ rad/s$

Therefore rate of change in the angle is 0.038\ rad/s

8 0

3 years ago

Round your answers to one decimal place.this parallel circuit has two resistors at 15 and 40 ohms. what is the total resistance?

lubasha [3.4K]

1) The equivalent resistance of two resistors in parallel is given by:
$\frac{1}{R_{eq}}= \frac{1}{R_1}+ \frac{1}{R_2}$
so in our problem we have
$\frac{1}{R_{eq}} = \frac{1}{15 \Omega}+ \frac{1}{40 \Omega}=0.092 \Omega^{-1}$
and the equivalent resistance is
$R_{eq} = \frac{1}{0.092 \Omega^{-1}}=10.9 \Omega$

2) If we have a battery of 12 V connected to the circuit, the current in the circuit will be given by Ohm's law, therefore:
$I= \frac{V}{R_{eq}}= \frac{12 V}{10.9 \Omega}=1.1 A$

4 0

3 years ago

Read 2 more answers

What are the charges of the subatomic particles?

kotegsom [21]

A particle smaller than an atom or a cluster of such particles

3 0

3 years ago

Winds that blow from the north and south poles

Gennadij [26K]

Winds that blow from the north and south poles would be called katabatic winds. I'm not sure if I spelled that right, but that's the answer I hope.

8 0

3 years ago