They can't hear an echo in small room because in it the sound can't be reflected back. For an echo of a sound to be heard,the minimum distance between the source of sound and the walls of the roomshould be 17.2 m. Obviously,in asmall room echoes cannot beheard.
So he has 7 sheepleft if i did it correctly
15-8=7
Answer:
the average speed of the car is 170 mph.
Explanation:
Given;
initial speed, u = 70 mph
time of motion, t₁ = 3 hours
final speed, v = 20 mph
time of motion, t₂ = 2 hours
The average speed of the car is calculated as;
Therefore, the average speed of the car is 170 mph.
An Earth revolution is a trip around the sun in a closed path (relative to the sun).
The path is very nearly an ellipse with the sun at one focus, and a little less nearly a circle with the sun at the center.
One complete revolution takes roughly 365.24 days, and at that point, the Earth immediately begins another one.
We have a special word that we use to refer to that special period of time. In English, it's called a "year".