A an opanque object is compared to a black T shirt
Answer:
120 volts is the root mean square (rms) average of the voltage as it varies with time.
Explanation:
A. The average voltage over many weeks of time (false)
Reason: Average AC voltage over one cycle is cycle (from one peak to other) is zero and so over many weeks of time it is zero.
B. The peak voltage from an AC wall receptacle (false)
Reason: The peak voltage of an AC source in North America is zero.
C. The arithmetic mean of the voltage as it varies with time (false)
Reason: Arithmetic mean AC voltage over one cycle is cycle (from one peak to other) is zero and so over many weeks of time it is zero.
D. One-half the peak voltage (false)
Peak voltage =170 Volts
One-half the peak voltage = 85 volts
E. The root mean square (rms) average of the voltage as it varies with time (True)
Reason:
The peak voltage and root mean square voltage are related by:

Average value of voltage over one cycle is zero, so instead of calculating average voltage for AC peak voltage is first squared and the mean is calculated.
Answer:
B.The linear velocity of the gears is the same. The linear velocity is 432π centimeters per minute.
Explanation:
As we know that the small gear completes 24 revolutions in 20 seconds
so the angular speed of the smaller gear is given as


Now we know that the tangential speed of the chain is given as

so we have



Since both gears are connected by same chain so both have same linear speed and hence correct answer will be
B.The linear velocity of the gears is the same. The linear velocity is 432π centimeters per minute.
|Average acceleration| = (change in speed) / (time for the change)
Change in speed = (speed at the end) minus (speed at the beginning)
= (40 m/s) - ( 0 )
= 40 m/s .
|Average acceleration| = (40 m/s) / (60 sec) = 2/3 m/s² .
Which is a substance that takes the shape and volume of its container?
liquid