3, protons are positive and there are 3 positive atoms visible
Answer:

Explanation:
The difference of electric potential between two points is given by the formula
, where <em>d</em> is the distance between them and<em> E</em> the electric field in that region, assuming it's constant.
The electric field formula is
, where <em>F </em>is the force experimented by a charge <em>q </em>placed in it.
Putting this together we have
, so we need to obtain the electric force the charged ball is experimenting.
On the second drop, the ball takes more time to reach the ground, this means that the electric force is opposite to its weight <em>W</em>, giving a net force
. On the first drop only <em>W</em> acts, while on the second drop is <em>N</em> that acts.
Using the equation for accelerated motion (departing from rest)
, so we can get the accelerations for each drop (1 and 2) and relate them to the forces by writting:


These relate with the forces by Newton's 2nd Law:


Putting all together:

Which means:

And finally we substitute:

Which for our values means:

Answer:
force (tension) of 29.4 N (upward) in 100 cm
force (tension) of 58.4 N (upward) in 200 cm
Explanation:
Given:
Length of tube = 5 m (500 cm)
Mass of tube = 9
Suspended vertically from 150 cm and 50 cm.
Computation:
Force = Mass × gravity acceleration.
Force = 9.8 x 9
Force = 88.2 N
So,
Upward forces = Downward forces
D1 = 150 - 50 = 100 cm
D2 = 150 + 50 = 200 cm
And F1 = F2
F1 x D1 = F2 x D2
F1 x 100 = F2 x 200
F = 2F
Total force = Upward forces + Downward forces
3F = 88.2
F = 29.4 and 2F = 58.8 N
force (tension) of 29.4 N (upward) in 100 cm
force (tension) of 58.4 N (upward) in 200 cm