Answer:
C
<span>
An
axe is a mechanical device with two inclined planes, thick at one end and
tapers to a thin edge and when it is used to chop wood, the axe blade acts as a
wedge and changes the direction of the input force. When the axe blade
penetrates the wood, a portion of the downward force of the blade is changed to
sideways forces, which are perpendicular to each external of the blade and the sideways forces
cause the wood to split in contrasting directions.</span>
Hi
I think the answer is:
GRAVITATIONAL POTENTIAL ENERGY TRANSFORMS INTO KINETIC ENERGY.
HOPE IT HELPS.
The correct answer is:
<span>A. electron attraction between electron and nucleus = centripetal force of the orbiting electron
In fact, Bohr model depicts the atom as a nucleus surrounded by electrons in circular orbit around it, similar to the planets around the Sun. The centripetal force that keeps the electrons in circular motion around the nucles is provided by the electrostatic force between the electrons and the nucleus, so option A is the correct one.</span>
Well, we know that the total energy in a closed system remains constant.
The problem with the story of Eva is that she is not in a closed system.
If the dark room were really a closed system, then she could press the
button or turn the switch all day, and the lamp could not light. It needs
electrical energy coming in from somewhere in order to turn on.
Let's say that Eva used her arm muscles to strike a match and light the
candle on the table. Then we would have have food energy, muscle
energy, chemical energy in the match, chemical energy in the candle,
heat and light energy coming out of the candle, heat energy soaking into
her hand, light energy bouncing off of the book and into her eyes ... all
going on during the story, and the sum total of all of them would remain
constant.
