Answer:
Average speed = 13.5 m/s
Explanation:
Since the car is running at a speed of 27 m/s and it stops after 3 seconds by applying the brake. Therefore, the initial speed of the 27 m/s and final speed is 0.
Use below formula to find the average speed :
Average speed = (Initial speed + final speed ) / 2
Average speed = (27 + 0 ) / 2
Average speed = 13.5 m/s
The first human made object made to orbit earth was the Soviet Union's Sputnik 1, it launched the 4th of October 1957.
Answer:
The power output of this engine is 
The the maximum (Carnot) efficiency is 
The actual efficiency of this engine is 
Explanation:
From the question we are told that
The temperature of the hot reservoir is 
The temperature of the cold reservoir is 
The energy absorbed from the hot reservoir is 
The energy exhausts into cold reservoir is 
The power output is mathematically represented as

Where t is the time taken which we will assume to be 1 hour = 3600 s
W is the workdone which is mathematically represented as

substituting values

So


The Carnot efficiency is mathematically represented as



The actual efficiency is mathematically represented as

substituting values


Answer:
D. infinitely extended in all directions
Explanation:
A semi infinite solid is infinitely extended in every direction. It has a single surface and can extend when heat is applied.
The body of a semi infinite solid is idealised, that is, when there is heat present, it expands in all directions to infinity. It can be used for a thick wall because its shape can be changed when subjected to different levels of heat near its surface.
It is also expands as heat is applied because its thickness is negligible.
This idealized body is used for earth, thick wall, steel piece of any shaped quenched rapidly etc indetermining variation of temperature near its surface & other surface being too far to have any impact on the region in short period of time since heat doesn’t have sufficient time to penetrate deep into body thus thickness can be neglected