Answer:

Explanation:
Here we know that for the given system of charge we have no loss of energy as there is no friction force on it
So we will have


now we know when particle will reach the closest distance then due to electrostatic repulsion the speed will become zero.
So we have



so distance moved by the particle is given as



Explanation :
The forces acting on hot- air balloon are:
Weight, (W)
Force due to air resistance, (F)
Upthrust force, (U)
Its weight W is acting in downward direction. The upthrust force U acts in upward direction. When the balloon is moving upward, the air resistance is in downward and vice versa.
In this case, the hot-air balloon descends vertically at constant speed.
so, 
and 
so,
....................(1)
when it is ascending let the weight that it is releasing is R, so
..........(2)
solving equation (1) and (2)

2F is the weight of material that must be released from the balloon so that it ascends vertically at the same constant speed.
This question can be solved using the concept of friction energy.
The thermal energy change is b "258.4 J".
The change in thermal energy will be equal to the friction energy produced during the motion of the box.

where,
μ = coefficient of kinetic friction = 0.4
f = force applied = 38 N
d = distance traveled by the box = 17 m
Therefore,

<u>E = 258.4 J</u>
Learn more about friction energy here:
brainly.com/question/1343045?referrer=searchResults
Q= mcΔT
Where Q is heat or energy
M is mass, c is heat capacitance and t is temperature
You have to convert Celsius into kelvin in order to use this formula I believe
Celsius + 273 = Kelvin
21 + 273 = 294K
363 + 273 = 636K
Now...
Q= (0.003)(0.129)(636-294)
Q= 0.132 J if you are using kilograms, in terms of grams which seems more appropriate the answer would be 132J of energy.