The stylus of a phonograph record exerts a force of 7.7 x 10\(^{-2}\)N on a groove of radius 10\(^{-5}\)m. Compute the pressure exerted by the stylus on the groove
A
2.45 x 108 Nm-2
B
3.45 x 108 Nm-2
C
4.90 x 108 Nm-2
D
2.42 x 108 Nm-2
Verified Correct Answer: A.
Physical Principles & Numerical Solution
Pressure P = \(\frac{F}{A}\); Pressure P = \(\frac{F}{\pi r^2}\)
= \(\frac{7.7 \times 10^{-2}}{\pi \times 10^{-10}}\)
= 2.45 x 10\(10^8\)Nm\(^{-2}\)
Source: Myschool Past Questions Archive (Record #12271)