When air is blown across the top of an open <span>water bottle, air molecules in the bottle vibrate at a particular frequency and sound is produced in a process called "refraction".
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(C)
Explanation:
The circle has a radius r = 0.5 m, which means that its circumference C is
One revolution means that the stopper travels a distance equal to the circumference of the circle so the velocity of the stopper is
Answer:
Explanation:
Given
Force 
time interval 
Impulse is given by 
For two significant Figure
The answer should be B. According to the conservation of energy, the energy cannot be created nor destroyed, but it can be transformed. Since the object is moving down, that means its height is decreasing, causing the potential energy decreasing and the kinetic energy increasing to fulfill the conservation law.
The easiest way to explain it is roughly identical to the way that your teacher explained it in class. If there were any easier way ... like writing it here in a few paragraphs ... then that's what the teacher would have done. You would have been given the easy explanation on the first day of class, printed on one sheet of paper, and you would have had the rest of the year to practice it and get really good at it.
If the class spent a month teaching it, then that's about how long it takes. Sorry.
