Answer: It is the product of the (force)multiplied by the (perpendicular) distance from the line of action of the force to the pivot
Explanation:
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.
Answer:
plasma arc
cutting
Explanation:
It is plasma arc cutting because i think it is
Answer:attract each other
Explanation:
When two-sphere, one with a negative charge and another neutral is brought close together but do not touch then they try to attract each other.
This because of the polarization of the neutral sphere as it is placed in the vicinity of a negatively charged sphere. The negatively charged sphere will induce the positive charge in the neutral sphere and they will attract each other according to Columb law.