The stylus of a phonograph record exerts a force of 7.7 x 10-2N on a groove of radius 10-5m. 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
Correct Answer: Option A
Explanation
Pressure P = F/A
= F/πr2
= 7.7 x 10-2
π x (10-5)2
= 7.7 x 10-2
π x 10-10
= 2.45 x 108 Nm-2