The tape in a videotape cassette has a total
length 297 m and can play for 2.1 h. as the
tape starts to play, the full reel has an outer
radius of 47 mm and an inner radius of 10 mm.
at some point during the play, both reels will
have the same angular speed.
what is this common angular speed?
answer in units of rad/s.

1.37 rad/s

Explanation:

Given:

Total length of the tape is, m

Total time of run is, hours

We know, 1 hour = 3600 s

So, 2.1 hours = 2.1 × 3600 = 7560 s

So, total time of run is, s

Inner radius is,

Outer radius is,

Now, linear speed of the tape is,

Let the same angular speed be .

Now, average radius of the reel is given as the sum of the two radii divided by 2.

So, average radius is,

Now, common angular speed is given as the ratio of linear speed and average radius of the tape. So,

Therefore, the common angular speed of the reels is 1.37 rad/s.

if the person is shown to have +90n, then ans is -10n.

if the person is shown to have -90n, then ans is +10n.