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3 years ago

What are the comparisons and contrast of adaptation and natural selection? ASAP!!!!!!

Physics

1 answer:

Andre45 [30]3 years ago

5 0

Answer:

Natural selection is a mechanism, or cause, of evolution.

Explanation:

Adaptations are physical or behavioral traits that make an organism better suited to its environment. Heritable variation comes from random mutations.

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A student measures the voltage and current between two points in an electrical circuit. If the voltage is 220 V and the current

77julia77 [94]

Answer:

Your answer is C

Explanation:

V=IxR

220 divide by 1.2=183.0

The answer was probably a type error so it should be C

8 0

2 years ago

Why is the gravitational potential energy of an object 1 meter above the moon’s surface less than its potential energy 1 meter a

dsp73

Potential energy relative to the surface is

(mass) x (<span>acceleration due to gravity) x (height above the surface).

At 1.0 meter above the surface, that is

</span> (mass) x (<span>acceleration due to gravity) x (1.0 meter) .

The object's mass doesn't change, so the only thing that has any effect
on its potential energy at 1 meter above the surface is the acceleration
of gravity or, in other words, the surface of <em><u>what</u></em> ?

</span>

3 0

2 years ago

Two uniform, solid cylinders of radius R and total mass M are connected along their common axis by a short, light rod and rest o

sveta [45]

Explanation:

A) To prove the motion of the center of mass of the cylinders is simple harmonic:

System diagram for given situation is shown in attached Fig. 1

We can prove the motion of the center of mass of the cylinders is simple harmonic if

$a_{x} = -\omega^{2} x$

where aₓ is acceleration when attached cylinders move in horizontal direction:

<h3>PROOF:</h3>

rotational inertia for cylinders is given as:

$I=\frac{1}{2}MR^{2}$ -----(1)

Newton's second law for angular motion is:

∑τ = Iα ------(2)

For linear motion in horizontal direction it is:

∑Fₓ = Maₓ ------ (3)

By definition of torque:

τ = RF --------(4)

Put (4) and (1) in (2)

$RF=\frac{1}{2}MR^{2}\alpha$

from Fig 3 it can be seen that fs is force by which the cylinders roll without slipping as they oscillate

So above equation becomes

$f_{s}=\frac{1}{2}MR\alpha$ ------ (5)

As angular acceleration is related to linear by:

$a= R\alpha$

Eq (5) becomes

$f_{s}=\frac{1}{2}Ma_{x}$ ---- (6)

aₓ shows displacement in horizontal direction

From (3)

∑Fₓ = Maₓ

Fₓ is sum of fs and restoring force that spring exerts:

$\sum F_{x} = f_{s} - kx$ ----(7)

Put (7) in (3)

$f_{s} - kx = Ma_{x}$ [/tex] -----(8)

Using (6) in (8)

$\frac{1}{2}Ma_{x} - kx =Ma_{x}$

$a_{x} = \frac{2k}{3M} x$ --- (9)

For spring mass system

$a= -\omega^{2} x$ ----- (10)

Equating (9) and (10)

$\omega^{2} = \frac{2k}{3M}$

$\omega = \sqrt{ \frac{2k}{3M}}$

then (9) becomes

$a_{x} = - \omega^{2}x$

(The minus sign says that x and aₓ have opposite directions as shown in fig 3)

This proves that the motion of the center of mass of the cylinders is simple harmonic.

<h3 /><h3>B) Time Period</h3>

Time period is related to angular frequency as:

$T=\frac{2\pi }{\omega}$

$T = 2\pi \sqrt{\frac{3M}{2k}$

5 0

3 years ago

A suitcase (mass m = 18 kg) is resting on the floor of an elevator. The part of the suitcase in contact with the floor measures

Sindrei [870]

Answer:

P=2736 Pa

Explanation:

According to Newton we have that:

∑ $F=m*a\\$

A force is exerted by the elevator to the suitcase, according to 3th Newton's law an equal force but in the opposite direction will appeared on the suitcase, that is:

∑ $F=m*g+m*a=m*(g+a)$

$F=205.2N$

We know that the pressure is given by:

$P=\frac{F}{A}\\P=\frac{205.2N}{(0.50m)*(0.15m)}\\P=2736N/m^2=2736Pa$

6 0

3 years ago

Which way does current always flow?

Phoenix [80]

Answer:

Electrons move through the wires in the opposite direction.

Explanation:

The direction of an electric current is by convention the direction in which a positive charge would move. Thus, the current in the external circuit is directed away from the positive terminal and toward the negative terminal of the battery.

3 0

2 years ago