Question

A disc is rotating at the rate 72 revolutions per minute on its axis. the velocity of a point on the disc which is 25 cm away from its centre is nearly on the disc

Answer 1

Explanation:

V = R * omega(w)

25* 2π72/60 =60π cm/sec

Answer 2

Answer:

The velocity at a point of 25 cm on the disc is 1.88m/s.

Explanation:

Given the rate of rotation of a disc, $n=72 rev/ min$

Distance of the point from the centre of the disc, $r= 25cm=0.25m$

1 revolution is equal to 2π radians,

then in units of rad/s, the angular velocity $\omega$ is  given by

$\omega=2\pi n=2\pi \times\frac{72}{60} ~rad/s$

The relation between linear velocity and angular velocity is given by, $v=r\omega$

$=0.25\times2\times\frac{22}{7} \times\frac{72}{60}$  

$=0.05\times\frac{22}{7} \times{12}$

$=1.88m/s$

Therefore, the velocity at a point of 25 cm on the disc is 1.88m/s.