Question

A block hangs from a string wrapped on a disc of radius 20 cm free to rotate about its axis which is fixed in a horizontal position, If the angular speed of the disc is 10 rad/s at some instant, with what speed is the block going down at that instant.

Answer 1

Given in the question.

Distance r = 20 cm or 0.20 m

Angular speed ω = 10 rad/s

Speed of the block , v =?

Now we know that if speed is going down at instant then,

$v = \omega r$
v= 10 × 0.20

v=2 m/s


Since v is the linear speed of the ring and also the rim of the disc. Hence the block going downward with a speed of 2m/s.


Hope it Helps :-)

Answer 2

Thanks for your question!

     Given => Distance (r) = 20 cm (multiplied by 10 we assume) or 0.20 m
Angular speed ω = 10 rad/s

Speed of the block (v) = ωr =  10 × 0.20

    Hence, v = 2m/s. And at 2m/s speed is the block going down at that instant.