12 MPH
I DIDNT do the math my brother did hes in colledge so good lucks guys
The answer & explanation for this question is given in the attachment below.
New rock get on top of old rock to form new layers of rock
Answer:
Option D
490 J
Explanation:
When at a height of 100 am above and released, the ball initially posses only potential energy. When it falls, some potential energy is converted to kinetic energy.
Initial potential energy= mgh where m is the mass, g is the acceleration due to gravity and h is height. Substituting 1 Kg for m, 9.81 for g and 100 m for h then
PE initial = 1*9.81*100= 981 J
At 50 m, PE will be 1*9.81*50=490.5 J
Subtracting PE at 50 m from initial PE we get the energy that has been converted to kinetic energy hence
981-490.5= 490.5 J
Approximately, 490 J
Answer:

Explanation:
Assume a point sound source that emits a sound power<em> P </em>(in W) evenly in all directions of space. Let us also assume that the medium does not absorb this sound power when it passes through it. At a distance<em> d </em>from the source this power will have been evenly distributed over the surface of a sphere of radius <em>d</em>. Therefore, the acoustic intensity I at distance d will be worth:

This is the expression of the so-called<em> law of the square of distance: "the intensity is inversely proportional to the square of the distance to the source (considered punctual)".</em>
So





