Answer:
197 hits/s
Explanation:
If the record is turning at the rate of 33 rev/min that means it's turning
[tex]\omega = 33rev/min*2\pi rad/rev*\frac{1}{60}min/sec = 3.456 rad/s[/tex]
If the groove is being played at radius of 10 cm (or 0.1m), that means the record is rotating with the speed of:
[tex]\omega*r = 3.456*0.1 = 0.346 m/s[/tex]
The goove bumps is uniformly separated at 1.75 mm(or 0.00175m/bump) bumps. So the number of hits per second it should be
[tex]\frac{0.346}{0.00175} = 197.47 \approx 197 hits/s[/tex]