Answer:
The distance covered by the rocket after fuel ran out is 
Explanation:
Given that the rocket moves with an acceleration 
time 
Since the rocket starts from rest initial velocity 
The distance it travelled within this time is given by

Velocity at this point is given by 

Given that at this height it runs out of fuel but travels further. Here final velocity
(maximum height), initial velocity
and time to zero velocity 
Thus it travels
more after fuel running out. The distance covered during this period is given

30 + 6 = 36
36/12 = 3
So, it would take it 3 hours to go 12 kms downstream.
Note that we added 30 and 6 because it was going downstream. If it was going upstream, then we would have had to subtract.
Answer:
KE = 1/2mv^2
KE = 1/2(24)(3^2)
KE = 12(9)
KE = 108 J
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Answer:
The electric force between them is 878.9 N
Explanation:
Given:
Identical charge
C
Separation between two charges
m
For finding the electrical force,
According to the coulomb's law

Here, force between two balloons are repulsive because both charges are same.
Where 

N
Therefore, the electric force between them is 878.9 N