I believe it is A. Electrons reside in known positions in fixed orbits around the nucleus
Answer:
(D) It is equal to the original velocity of the skater.
Explanation:
The velocity of the center of mass of a system is

The velocity of the center of mass is constant if there is no external force, because the total momentum of the whole system is conserved.
So, before the snowball is thrown, the velocity of the center of mass is equal to that of the skater. This velocity will always be equal to the velocity of the center of mass of the system.
Answer: DC Current
Explanation:
Battery is a source of constant potential difference and it will create a constant voltage across any conductor
due to this constant voltage difference the current in this conductor will remain constant
So here since the voltage across the conductor is constant so we can say that current in the conductor will remain constant and hence this is known as DC current.
While for variable current in direction and magnitude is to be obtained only when the conductor is connected with AC voltage source as we know that AC voltage is variable with magnitude and direction both
A battery is the power source for DC type of current. A battery is a source of constant potential difference that produces a constant current unlike in AC source where the voltage and hence the current changes its polarity continuously.Hence, the current produced by battery is direct current and not Alternating current.
Hope this helps........ Stay safe and have a Merry Christmas!!!!!! :D
Answer:
892 Hz or 842 Hz
Explanation:
Given
The frequency of first guitar is 867 Hz
Beat is produced for every 0·04 s
∴ Beat has a time period of 0·04 s
<h3>Beat frequency is defined as the inverse of the time period of the beat </h3>
Beat frequency = 1 ÷ (Time period) = 1 ÷ 0·04 = 25 Hz
Let the frequency of the second guitar be f Hz
<h3>Beat frequency is defined as the absolute difference between the two frequencies</h3>
∴ Beat frequency = (867 - f) or (f - 867)
First case
25 = 867 - f ⇒ f = 842 Hz
Second case
25 = f - 867 ⇒ f = 892 Hz
∴ Possible frequencies of second guitar could be 892 Hz or 842 Hz