Tin is Sn, atomic number 47 is Silver, Mass of sodium is 22.9 u
Answer:
Ondas y sonido. Una onda es una perturbación que avanza o que se propaga en un medio material o incluso en el vacío. ... El sonido es un tipo de onda mecánica que se propaga únicamente en presencia de un medio material.
Explanation:
<span>This
is because astronomers have discovered that
the Crab Nebula is 6500 light years from earth. This means it takes 6500 earth years
for light to get from the Crab Nebula to
earth. Therefore, if we are able to observe the
Crab Nebula and beyond it then it means that earth has been in existence for 6500 years and
over. </span>
The general formula to calculate the work is:
where F is the force, d is the displacement of the couch, and 
is the angle between the direction of the force and the displacement. Let's apply this formula to the different parts of the problem.
(a) Work done by you: in this case, the force applied is parallel to the displacement of the couch, so 
and 
, therefore the work is just equal to the product between the horizontal force you apply to push the couch and the distance the couch has been moved:
(b) work done by the frictional force: the frictional force has opposite direction to the displacement, therefore 
and 
. Therefore, we must include a negative sign when we calculate the work done by the frictional force:
(c) The work done by gravity is zero. In fact, gravity (which points downwards) is perpendicular to the displacement of the couch (which is horizontal), therefore 
and 
: this means
.
(d) Work done by the net force:
The net force is the difference between the horizontal force applied by you and the frictional force:
And the net force is in the same direction of the displacement, so and and the work done is
Transverse waves move perpendicular to their energy
