Question

The 8.00-cm long second hand on a watch rotates smoothly.
What is its angular velocity?
What is the speed of the tip of the hand?

Answer 1

@iphan7 is angular velocity be given ?

Answer 2

I don't know

Answer 3

what formular do you use? r= 8.0 cm is it right?

Answer 4

okk,
lets assume that angular velocity be ω

Answer 5

and radius is 8 cm

Answer 6

now use :-
\[\large \bf v=\omega \times r\]

Answer 7

understood? @Iphan7

Answer 8

so there is only 1 number is given how can I calculate?

Answer 9

\[\large \bf v= \omega \times r\]
\[\large \bf v= \omega \times 8=8 \omega=\color{red}{Answer}\]

Answer 10

the answer need to be in rad/s

Answer 11

see, second hand moves \(\large \bf 2 \pi r\) to complete one revolution in 60s.
therefore,
\[\large \bf \omega=\frac{2 \pi r}{60}=\frac{2 \pi \times 0.08}{60}=0.0026 \pi ~rad/s\]

Answer 12

I got it. I have to calculate for the V by calculate the perimeter of circle 1st

Answer 13

yes !! (mentioned above)

Answer 14

thanks for reponsed

Answer 15

!!!!