answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Rufina
1 month ago
13

Ancient cultures built some impressive structures that incorporated astronomical functions and information (Stonehenge, Chichen

Itza, the Great Pyramid). A friend or acquaintance of yours tries to argue that some of these structures and artifacts are evidence of "ancient astronauts" or visits by intelligent aliens. How would you rebut or argue against this idea?
Physics
1 answer:
Ostrovityanka [3.2K]1 month ago
4 0
Hahanshshsnsdndjdjdndn
You might be interested in
A 68 kg hiker walks at 5.0 km/h up a 9% slope. The indicated incline is the ratio of the vertical distance and the horizontal di
Softa [3030]

The formula used to calculate power is:

Power = Work / Time

Where Work is defined as Force multiplied by Distance, hence:

Power = Force * Distance / Time

This can also be expressed as:

Power = Force * Velocity<span>


Converting the velocity from km/h to m/s:</span>

Velocity = (5 km / h) (1000 m / km) (1 h / 3600 s)<span>
Velocity = 1.39 m/s 

</span>

The calculated force corresponds to the vertical component of the hiker's weight:

Force = Wy * g = W * sin θ * g

 

To find the angle θ, we utilize the slope, which is defined as:

slope = tan θ = ratio of vertical to horizontal distance

tan θ = 0.09

θ = 5.14˚

Thus, we have Force = 68 kg * sin(5.14˚) * 9.8 m/s²<span>
Force = 666.4 * sin(5.14) = 59.73 N 

</span>

<span>Now, let's compute the power:
<span>Power = 59.73 N * 1.39 m/s = 82.96 W
Given the hiker's efficiency is at 25%, we can find the metabolic power: 
<span>Metabolic Power = 82.96 W / 0.25 = 331.83 watts </span></span></span>
6 0
2 months ago
Planting of crops to purify -lucern, shrubs, trees(possible job creation)
kicyunya [3294]
These plants were utilized to eliminate harmful substances from the environment. In today's world, such crops have evolved into a significant asset and can be a source of profit when managed properly, creating multiple job opportunities along the way. Hope this information is useful.
8 0
1 month ago
Read 2 more answers
In mammals, the weight of the heart is approximately 0.5% of the total body weight. Write a linear model that gives the heart we
Yuliya22 [3333]

Answer:

The typical weight of a human heart is approximately 0.93 lbs.

Explanation:

Based on this,

the heart's weight constitutes about 0.5% of total body mass.

Total human weight = 185 lbs

Let the entire body weight be represented as w and the heart's weight as w_{h}.

We aim to determine the heart's weight for a human

Using the provided information

w_{h}=0.5\times w

Where, h = heart weight

w = human weight

w_{h}=\dfrac{0.5}{100}\times 185

w_{h}=0.93\ lbs

The final weight of a human heart is 0.93 lbs.

8 0
3 months ago
A person shooting at a target from a distance of 450 metres finds that the sound of the bullet hitting the target comes 1 / 2 se
Sav [3153]

Answer:

1350 m/s

Clarification:

Bullet speed

The bullet travels 450 m

Sound travels a distance of 450 m

Using the equation S= V × t

==> t= S/V

Thus, the time for the bullet t1=450/vb

and the sound's travel time t2=450/vs

Given that there's a 1/2 sec interval from when the shot is fired to the moment the shooter hears the sound

==>  t1+t2= 1/2 sec

==> 450/vb+450/vs=0.5sec  ---- (1)

At a distance 'x' from both the gun and target, it takes 3 seconds for a person to hear the bullet sound from firing to impact.

Firing sound duration

n

Distance =x m

Speed of sound = V

time =T1

==> T1 = x/vs

During this time period, the bullet covers 450 m and the sound of impact travels a distance 'x'

The time taken for sound = 450/vb

The time it takes sound to travel distance 'x'= x/vs

therefore let T2= 450/vb + x/vs

However, all this occurs within 3 seconds, i.e., T = 3 sec

because firing takes place before hitting the target, implying the strike sound is heard in time T = T2-T1= 450/vb + x/vs -x/vs

Making T= 3sec

==> 3= 450/vb

==> vb= 1350 m/s

From equations 1 and 2

applying the same principle, in 3 seconds the observer sees the bullet travel 450 m and perceives the sound


3 0
1 month ago
Two vectors A⃗ and B⃗ are at right angles to each other. The magnitude of A⃗ is 4.00. What should be the length of B⃗ so that th
serg [3582]

Answer:

B= \sqrt{65} ≅8.06

Explanation:

Applying the Pythagorean theorem:

C^{2}= A^{2} + B^{2}

Here, C denotes the hypotenuse length, while A and B signify the lengths of the other two sides of the triangle. We can calculate B's length knowing the hypotenuse is 9 and A is 4.

9^{2}=4^{2} + B^{2}

81= 16+ B^{2}

81-16= B^{2}

B= \sqrt{65} ≅8.06

8 0
3 months ago
Other questions:
  • What is the maximum value the string tension can have before the can slips? The coefficient of static friction between the can a
    7·1 answer
  • Kayla, a fitness trainer, develops an exercise that involves pulling a heavy crate across a rough surface. The exercise involves
    6·1 answer
  • Two resistors ( 3 ohms &amp; 6 ohms) in a series circuit with a power supply = 12 volts. The current through resistor 6 ohms is
    15·1 answer
  • Early investigators (including Thomas Young) measured the thickness of wool fibers using diffraction. One early instrument used
    15·1 answer
  • Use the momentum equation for photons found in this week's notes, the wavelength you found in #3, and Plank’s constant (6.63E-34
    14·2 answers
  • A ball is fired at an angle of 45 degrees, the angle that yields the maximum range in the absence of air resistance. What is the
    6·2 answers
  • A roller coaster moving along its track rolls into a circular loop of radius r. In the loop, it is only affected by its initial
    7·2 answers
  • All forces on the bullets cancel so that the net force on a bullet is zero, which means the bullet has zero acceleration and is
    5·2 answers
  • What is the average acceleration of a car that is initially at rest at a stoplight and then accelerates to 24 m/s in 9.4 s?
    15·2 answers
  • On a foggy day, you are driving at 70 mph and Granny is driving at 50 mph. As you try to pass her, you both see an overturned tr
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!