The answer is A. speed
hope this helps! :D
Answer:
Hits per second=199 hit/s
Explanation:
#Given the angular velocity, 
, radius of the record 
and the distance between any two successive bumps on the groove as 
.
The linear speed of the record in meters per second is:
#From 
above, if the bumps are uniformly separated by 1m, then the rate at which they hit the stylus is:
Hence the bumps hit the stylus at around 199hit/s
Answer:
This can be translated to:
"find the electrical charge of a body that has 1 million of particles".
First, it will depend on the charge of the particles.
If all the particles have 1 electron more than protons, we will have that the charge of each particle is q = -e = -1.6*10^-19 C
Then the total charge of the body will be:
Q = 1,000,000*-1.6*10^-19 C = -1.6*10^-13 C
If we have the inverse case, where we in each particle we have one more proton than the number of electrons, the total charge will be the opposite of the one of before (because the charge of a proton is equal in magnitude but different in sign than the charge of an electron)
Q = 1.6*10^-13 C
But commonly, we will have a spectrum with the particles, where some of them have a positive charge and some of them will have a negative charge, so we will have a probability of charge that is peaked at Q = 0, this means that, in average, the charge of the particles is canceled by the interaction between them.
