Explanation:
u=40
v=?
h=?
v²-u²=2gs
0²-40²=2×10×s
160=20s
s=160/20
=80m/s
total distance= upward distance ×downward distance
=80+80
=160m
total displacement=0 because u and v is the same.
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.
The correct answer is:
<span>Become positively or negatively charged
In fact, an insulator is a material where charges cannot move freely. Therefore, it can be positively or negatively charge (for example, if it is rubbed against another object, the insulator can remain with an excess of charge), but it cannot transfer charge to other objects.</span>