Question

The tips of the blades in a food blender are moving with a speed of $20m/s$ in a circle that has a radius of $0.06m$. How much time does it take for the blades to make one revolution? (in seconds)

• A. $0.019$
  
• B. $0.2$
  
• C. $0.3$
  
• D. $0.6$
  

Answer 1

The correct option is A $0.019$

Angular velocity (ω) is the rate of change of an angle per unit time

Angular Velocity($\omega )$ = $\frac{v}{R}$ = $\frac{2\pi }{T}$

= $\frac{20}{0.06}$ = $333.3rad/s$ = $\frac{2\pi }{T}$

$T$= $\frac{2\pi }{333.3}$ $=0.01884sec\approx 0.019sec$