Answer:2.4
Explanation:basically 2.4 = 2.500 kg and then we add 3.4 seconds in all of them 4.0 + 3.4 = 2.5 ok
As the plastic sphere is charged, therefore it experience an electric force when placed in an electric fields and also experiences gravitational force acts downward so the electric force must act upward.
Let
is electric force and
is gravitational force.
If these forces are balanced, therefore
or 
Given,
and
.
Substituting these values in above equation we get,

Thus, the magnitude of electric field is
.
As the charge is negative, the electric field at the location of the plastic sphere must be pointing downward.
What distinguishes a nebula and a star is that a nebula is a cloud of gas and dust in outer space, visible in the night sky either as an indistinct bright patch or as a dark silhouette against other luminous matter. And a star is a<span> type of astronomical object consisting of a luminous spheroid of plasma held together by its own gravity.</span>
Choice D). is on the right track, but it's stated incorrectly.
The wavelengths of light coming from a galaxy that's moving toward us <em>are </em>
<em>shorter</em> than they were when they left the galaxy. When we see them, they're
shorter than they should be.
(This is called a "blue shift" in the spectrum of the galaxy, because blue is the
short-wavelength end of the spectrum of visible light. If the wavelength of some
light somehow becomes shorter, then the color of the light changes toward the
direction of blue.)
If the source of light is moving toward us, then the wavelength we see is shorter
than it should be. If the source is moving away from us, then the wavelength
we see is longer than it should be. The whole trick to this is knowing <u>what</u> the
wavelength of the light we see <em>should be</em> !
B. chemical energy
because thats the only way i see it out of your anwser choices hope i helped