Question

The force on a phonogram needle of cross-secton of radius of 0.01cm , is 1.5N .Find the

pressure it exerts on the record in (i) Pa (ii) atm​

Answer 1

Given:

The force on a phonogram needle of cross-secton of radius of 0.01cm , is 1.5N .

To find:

Find the pressure it exerts on the record in (i) Pa (ii) atm​

Solution:

From given, we have,

The radius of needle = r = 0.01 m

The force on a phonogram needle = F =  1.5 N

The pressure the needle exerts on the record is,

Pressure = Force/Area

= 1.5/πr²

=  1.5/(3.14 × 0.01²)

∴ Pressure exerted = 4777 N/m²

(i) Pa

1 N/m² = 1 Pa

∴ Pressure exerted = 4777 Pa

(ii) atm​

101324.997664 N/m2 = 1 atm

∴ Pressure exerted = 0.04714532 atm