Answer:
B
Explanation:
The iris controls the amount of light that enters the eye by opening and closing the pupil. The iris uses muscles to change the size of the pupil. These muscles can control the amount of light entering the eye by making the pupil larger (dilated) or smaller (constricted).
 
        
                    
             
        
        
        
Answer:
a) The magnitude of the force is 968 N
b) For a constant speed of 30 m/s, the magnitude of the force is 1,037 N
Explanation:
<em>NOTE: The question b) will be changed in other to give a meaningful answer, because it is the same speed as the original (the gallons would be 1.9, as in the original).</em>
Information given:
d = 106 km = 106,000 m
v1 = 28 m/s
G = 1.9 gal
η = 0.3
Eff = 1.2 x 10^8 J/gal
a) We can express the energy used as the work done. This work has the following expression:

Then, we can derive the magnitude of the force as:

b) We will calculate the force for a speed of 30 m/s.
If the force is proportional to the speed, we have:

 
        
             
        
        
        
Answer:
Scientists have studied eclipses since ancient times. Aristotle observed that the Earth's shadow has a circular shape as it moves across the moon. He posited that this must mean the Earth was round. Another Greek astronomer named Aristarchus used a lunar eclipse to estimate the distance of the Moon and Sun from Earth
 
        
                    
             
        
        
        
Earthquakes occur in the crust or upper mantle, from the earth’s surface to about 400 miles below the surface. But the very deepest earthquakes only occur at subduction zones where cold crustal rock is being pushed deep into the earth. In California, earthquakes are almost all in the top 15 miles of the crust, except in northern California along the Cascadia Subduction Zone, which extends into Oregon, Washington, and British Columbia.(tectonic plate boundaries)