Answer: The average speed is 27,24 mph (exactly 1008/37 mph)
Explanation:
This is solved using a three rule: We know the speeds and the distances, what we can obtain from it is the time used. It is done like this:
1h--->18mi
X ---->20 mi, then X=20mi*1h/18mi= 10/9 h=1,111 h
1h--->56mi
X ---->20 mi, then X=20mi*1h/56mi= 5/14 h=0,35714 h
Then the average speed is calculated by taking into account that it was traveled 40mi and the time used was 185/126 h=1,468 h and since speed is distance over time we get the answer. Average speed= 40mi/(185/126 h)=1008/37 mph=27,24 mph.
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
See the attached picture for answers
I think the correct answer from the choices listed above is option D. The model of the universe that suggests that the sun is the center of the universe was first brought by Copernicus. His model is known as the "Sun centered model".
Answer:
Resistance will become 4 times the previous value
Explanation:
We have given current in the circuit i = 2.4 A
According to ohm's law current in the circuit is given by 
So 
............eqn 1
Now voltage is increased to 4 times so new voltage = 4 V
And current in the circuit is same as 2.4 A
We have to fond the resistance so that after increasing voltage current will be same
So 
..........eqn 2
Dividing eqn 1 and 2
So resistance will become 4 times the previous value
