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sleet_krkn [62]
3 years ago
6

Darwin believed that emotional expressions began as ________ that came to have evolutionary value because they ________. Select

one: a. physiological reactions; increased the efficiency of bodily reactions b. communication devices; increased the efficiency of bodily reactions Incorrect c. physiological reactions; convey emotional states to other members of the species d. random mutations; convey expectations to other members of the species
Physics
1 answer:
Strike441 [17]3 years ago
5 0

Answer:

c. physiological reactions; convey emotional states to other members of the species

Explanation:

Darwin believed that emotional expressions began as physiological reactions that came to have evolutionary value because they convey emotional states to other members of the species. These reactions are used by many different types of species to convey various things.

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Why is it important that two different metals are used in building an electrochemic<br> cell?
Mnenie [13.5K]

Answer:

Explanation:

They need a galvanic difference. Or saying that less technically,  they need to have different electron attraction, so that one can collect electrons (oxidation/reduction)  and flow current from the other.  :)

5 0
3 years ago
In a pendulum system, does the kinetic exceed the potenial energy? Explain.
STALIN [3.7K]
At the bottom of the rotation, the kinetic far exceeds the potential. However, at both tops, potential exceeds kinetic. 
5 0
3 years ago
An electron moves in a circular path perpendicular to a constant magnetic field with a magnitude of 2.50 mT. The angular momentu
liberstina [14]

Answer:

Explanation:

The angular momentum of electron mvR = 6 x 10⁻²⁵  Js

Magnetic field B = 2.5 x 10⁻³ T

radius of circular path R = mv / Bq

where m is mass , v is velocity and q is charge on electron

R² = mvR / Bq

R² = 6 x 10⁻²⁵ / 2.5 x 10⁻³ x 1.6 x 10⁻¹⁹

= 1.5 x 10⁻³

R = 3.87 x 10⁻² m

mvR = 6 x 10⁻²⁵

v = 6 x 10⁻²⁵  / mR

= 6 x 10⁻²⁵  / 9.1 x 10⁻³¹ x 3.87 x 10⁻²

= .17 x 10⁸

= 17 x 10⁶ m/s

6 0
3 years ago
A missle is fired horizontally with an initial velocity of 45 m/s from the top of a building 75 m high.
NARA [144]

The horizontal range of the missile is b) 176 m

Explanation:

The motion of the missile is a projectile motion, so it consists of two independent motions:  

- A uniform motion with constant velocity along the horizontal direction  

- A uniformly accelerated motion with constant acceleration (equal to the acceleration of gravity) in the vertical-downward direction  

To find the time of flight of the missile, we study the vertical motion. We can use the following suvat equation:

s=u_y t+\frac{1}{2}at^2

where:

s = 75 m is the vertical displacement of the missile (the height of the building)

u_y=0 is the initial vertical velocity  (the missile is thrown horizontally)

t is the time of flight

a=g=9.8 m/s^2 is the acceleration of gravity

Solving for t, we find the time of flight:

t=\sqrt{\frac{2s}{g}}=\sqrt{\frac{2(75)}{9.8}}=3.91 s

This means that the missile takes 3.91 s to reach the ground.

Now we study the horizontal motion: the missile moves with a constant horizontal velocity of

v_x = 45 m/s

Therefore, the distance covered in a time t is

d=v_x t

and by substituting t = 3.91 s, we find the horizontal range of the missile:

d=(45)(3.91)=176 m

Learn more about projectile motion:

brainly.com/question/8751410

#LearnwithBrainly

4 0
3 years ago
10. What is the acceleration due to gravity at a location
kherson [118]
The answer is 3) 3.00 m/s2
5 0
2 years ago
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