Answer:
1)
is<u> positive.</u>
<u></u>
2) 
Explanation:
<h2><u>
Part 1:</u></h2>
<u></u>
The charged rod is held above the balloon and the weight of the balloon acts in downwards direction. To balance the weight of the balloon, the force on the balloon due to the rod must be directed along the upwards direction, which is only possible when the rod exerts an attractive force on the balloon and the electrostatic force on the balloon due to the rod is attractive when the polarities of the charge on the two are different.
Thus, In order for this to occur, the polarity of charge on the rod must be positive, i.e.,
is <u>positive.</u>
<u></u>
<h2><u>
Part 2:</u></h2>
<u></u>
<u>Given:</u>
- Mass of the balloon, m = 0.00275 kg.
- Charge on the balloon,

- Distance between the rod and the balloon, d = 0.0640 m.
- Acceleration due to gravity,

In order to balloon to be float in air, the weight of the balloom must be balanced with the electrostatic force on the balloon due to rod.
Weight of the balloon, 
The magnitude of the electrostatic force on the balloon due to the rod is given by

is the Coulomb's constant.
For the elecric force and the weight to be balanced,

Answer:
16.1 N
Explanation:
From the question,
F = ma.............................. Equation 1
Where F = horizontal force, m = mass of the object, a = acceleration .
Given: m = 7.0 kg, a = 2.3 m/s²
Substitute this values into equation 1
F = (7.0×2.3)
F = 16.1 N.
Hence the magnitude of the horizontal force is 16.1 N
Answer:
total number of electron in 1 litter is 3.34 ×
electron
Explanation:
given data
mass per mole = 18 g/mol
no of electron = 10
to find out
how many electron in 1 liter of water
solution
we know molecules per gram mole is 6.02 ×
molecules
no of moles is 1
so
total number of electron in water is = no of electron ×molecules per gram mole × no of moles
total number of electron in water is = 10 × 6.02 ×
× 1
total number of electron in water is = 6.02×
electron
and
we know
mass = density × volume ..........1
here we know density of water is 1000 kg/m
and volume = 1 litter = 1 ×
m³
mass of 1 litter = 1000 × 1 × 
mass = 1000 g
so
total number of electron in 1 litter = mass of 1 litter × 
total number of electron in 1 litter = 1000 × 
total number of electron in 1 litter is 3.34 ×
electron
v₀ = initial speed as tarzan grabs the vine = 5.3 m/s
v = final speed as the tarzan reach the maximum height = 0 m/s
h = maximum height gained by the tarzan
m = mass of tarzan
using conservation of energy
initial kinetic energy = final kinetic energy + potential energy
(0.5) m v²₀ = (0.5) m v² + m g h
(0.5) v²₀ = (0.5) v² + g h
(0.5) (5.3)² = (0.5) (0)² + (9.8) h
h = 1.43 m