Answer:
Gravity, or gravitation, is a natural phenomenon by which all things with mass or energy-including planets,stars,galaxies, and even light-are brought toward one another.
Explanation:
Answer:
Just like lightning, the spark you see is the discharge of static electricity that equalizes the charges. When you touch a metal object and get a shock, electrons are travelling in between you and the object to equalize the charges of the two objects. The light that is seen is the plasma created by electrons jumping between objects which heats the air surrounding them.
Answer:
moving the boxes and the furniture up to the fifth floor.
Explanation:
The work done when moving an object up or down is equal to its change of gravitational potential energy:

where
m is the mass of the object
g is the gravitational acceleration
is the change in height of the object
We have two opposite situations:
1) when an object is moved upward,
is positive, so the work done W is positive as well: this means that we need to do work in order to move the object, because we have to "win" the effect of gravity, which pulls the object downward
2) when an object is moved downward,
is negative, so the work done W is negative as well: this means that we do not need to do work on the object, because it is already done by gravity, which pulls the object downward.
Therefore, more work is done when we are moving the boxes and the furniture up to the fifth floor.
Hey there! <span>The cohesive forces between liquid molecules are responsible for the phenomenon known as </span>surface tension<span>. The molecules at the </span>surface do<span> not have other like molecules on all sides of them and consequently they cohere more strongly to those directly associated with them on the </span>surface<span>. Hope this helps! :)</span>