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THE ELECTRIC FIELD. Each electric particle projects into space a field of electric force, and as the particles move along a wire, the lines of force move with them. |
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Energy. There is a law governing all natural phenomena. there is no exception to this law - it is exact so far as we know. The law is callled the conservation of energy. it states that there is a certain quantity, which we call energy, that does not change in manifold changes which nature undergoes. |
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NEWTON’S LAWS OF MOTION
According to Newton’s first law of motion, if no net force acts on it, a body at rest remains at rest and a body in motion remains in motion at constant velocity (that is, at constant speed in a straight line).
This law provides a definition of force: A force is any influence that can change the velocity of a body.
Two or more forces act on a body without affecting its velocity if the forces cancel one another out. What is needed for a velocity change is a net force, or unbalanced force. To accelerate something, a net force must be applied to it. Conversely, every acceleration is due to .................................... |
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CHAPTER 2 MOTION Velocity
The velocity of a
body is a vector quantity that describes both how fast it is moving and the
direction in which it is headed.
In the
case of a body traveling in a straight line, its velocity is simply the rate at
which it covers distance. The average velocity ¯v of such a body when it
covers the distance s in the time t is............................. |