Answer: two waves with identical crests and troughs meet
Explanation:
My teacher gave me the answer
Potential energy U = mgh
Given h = 123 m,
mg = F = 780 N
Then
U = (123)(780)
= 95940
= 9.59 x 10^4
If I drop my egg unprotected, then it will break.
Answer:
The distance in kilometers is 4012 ×
km.
Explanation:
We know that the conversion of 1 millimeters is equal to
meter. And then the conversion of 1 meter is equal to
km. Then the conversion of 1 millimeter to km will be
1 mm =
m
1 m =
km
So, 1 mm =
×
km =
km.
As here the the distance is 4012 mm, then the distance in km will be
4012 mm = 4012 ×
km.
So the distance is 4012 ×
km.
Answer:

Explanation:
The ball will rise decreasing its speed until it reaches the highest point where its speed will be zero. From this point the tennis ball will begin to fall again, in the free fall the tennis ball will gain speed but now in the opposite direction. When it returns to the same point where it was launched, its speed will be the same as the one that was launched but with the opposite sign.

We can check this using the equation:

where 
ang h is the height, but because the ball returns to the same point where it started, h =0
then


the initial and final velocity will be the same in number, but we know that the ball is going in the opposite direction, so the final velocity must have the opposite sign from the initial velocity
so if
,
