Question

A spaceman in training is rotated in a seat at the end of a horizontal rotating arm of length $5m$. If he can withstand acceleration upto $9\frac{m}{s^2}$, then what is the maximum number of revolutions per second permissible?
Take $g=10m/s^2$

• A. $13.5$rps
• B. $1.35$rps
• C. $0.657$rps
• D. $6.75$rps

Answer 1

The correct option is B $1.35$rps

Let the maximum number of revolutions per sec be $\omega$
Radius (r)= length of arm =5m
He can withstand a acceleration upto 9m/s^2
Therefore ${\omega }^{2}r$=9
$\omega =\sqrt{\frac{9}{5}}=1.35rps$