Question

A stone is tied to one end of string $50cm$ long and is whirled in a horizontal circle with constant speed. If the stone makes revolutions in $s$, then what is the magnitude of acce;leration of the stone:

• A. $493cm/s^2$
• B. $720cm/s^2$
• C. $8620cm/s^2$
• D. $990cm/s^2$

Answer 1

The correct option is A $493cm/s^2$

Radius $=r=50cm=0.5m$

In $20$ sec revolution $=10$

In $1$ sec revolution $=10/20=1/2$ Hz

$N=1/2Hz$

Now,

Angular velocity $=W=2\pi n=w=2\times 3.14\times 0.5$

Radial Acceleration $=w^{2}r$

Radial Acceleration $={\left(3.14\right)}^2\times 0.5m/s^2=4.93m/s^2=493cm/s^2$