Answer:

Explanation:
As we know that ball travels horizontal distance of 24.7 m with uniform speed 49.4 m/s
so we will have



now in the same time ball is turned by angle

now we know that



now the tangential speed of a point at equator is given as



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
A beat is an interference pattern between two sounds of slightly different frequencies, perceived as a periodic variation in volume whose rate is the difference of the two frequencies. Frequency beat is equal to,

The reference frequency in our case would be 392Hz, and since there is the possibility of the upper and lower range for the amount of beats per second that the two possible frequencies are heard would be


Therefore the two possible frequencies the piano wire is vibrating at, would be 396Hz and 388Hz
I believe your answer should be C. Speed.
Answer:
The width of the central bright fringe on the screen is observed to be unchanged is 
Explanation:
To solve the problem it is necessary to apply the concepts related to interference from two sources. Destructive interference produces the dark fringes. Dark fringes in the diffraction pattern of a single slit are found at angles θ for which

Where,
w = width
wavelength
m is an integer, m = 1, 2, 3...
We here know that as
as w are constant, then

We need to find
, then

Replacing with our values:


Therefore the width of the central bright fringe on the screen is observed to be unchanged is 