Answer:
<em>The average speed is 22.2 km/h</em>
Explanation:
<u>Average Speed</u>
Given an object travels a total distance d and took a total time t, then the average speed is:
The mailman first drives d1=7 km at v1=15 km/h. The time taken to drive is:
Then he drives d2=7 km at v2=43 km/h taking a time of:
The total time is
t=0.467 h + 0.163 h = 0.63 h
The total distance is
d = 7 km + 7 km = 14 km
The average speed is:
The average speed is 22.2 km/h
necessaryAnswer:
a)
b)
c)
d)
e) 3787.6 cycles
Explanation:
As this engine is ideal, the efficiency depends only on the temperatura of the reservoirs(in kelvin scale):
the efficiency is also related to the heat exchanged between the reservoirs:
Solving for and having in mind that :
The change of entropy for the hot reservoir:
Similar for the cold reservoir:
From the efficiency we can calculate the work that the engine can make for a cycle:
solving for W:
It will take the engine:
The gravitational attractions are greatest be when the objects have large masses and they're closer together. Their sizes don't matter.
Answer:
Because of inertia (Newton's First Law of motion)
Explanation:
According to Newton's First Law of motion:
"An object at rest (or in motion at constant velocity) will tend to stay at rest (or tend to keep moving with same velocity) unless acted upon an unbalanced force"
In this problem, the object we are analyzing is the coffee cup.
At the beginning, the cup is at rest, together with the car.
Later, the car starts moving when the light turns green.
If we apply Newton's First Law of motion to the cup, we see that the coffee cup tends to keep its state of rest: for this reason, as the car moves forward, the coffee in the cup will spill backward, into the rear seat. This property of an object to mantain its state of motion is also called as inertia.
I think Option B, i’m sorry if that’s wrong.