Answer:
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.
FOUR USES OF CONCAVE MIRROR:Satellite dishes,headlights of a car, telescopes used for astronomical studies, and shaving mirrors because of there curved and reflective surface.
FIVE USES OF LENSES: Camera lens ,microscopes ,magnifying glass,eyeglasses,projector
Here are the answers:
1. Geosphere (though the term lithosphere is mostly used)
2. Both ice and wind (glaciers, and really strong winds)
3. Water
4. Its inertia (the Earth is constantly "falling" towards the Sun due to its gravitational pull, but its inertia helps the Earth from maintaining its orbit.)
5. The rotating Earth
6. one year
7. The equator
8. It depends on how much of the sunlit side of the Moon faces the Earth
9. When an object in space comes between the Sun and a third object
10. D<span>ifferences in how much the Moon and the Sun pull on different parts of Earth
11. b. False
12. a. True
Hope my answers have come to your help.</span>