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:
The amount of energy required is
Explanation:
The energy required to convert the ice to steam is the sum of:
1) Energy required to raise the temperature of the ice from -20 to 0 degree Celsius.
2) Latent heat required to convert the ice into water.
3) Energy required to raise the temperature of water from 0 degrees to 100 degrees
4) Latent heat required to convert the water at 100 degrees to steam.
The amount of energy required in each process is as under
1)
where
' is specific heat of ice =
2) Amount of heat required in phase 2 equals
3) The amount of heat required to raise the temperature of water from 0 to 100 degrees centigrade equals
where
' is specific heat of water=
4) Amount of heat required in phase 4 equals
Thus the total heat required equals
Answer:
In the present study, the startle blink reflex is used as a measure of emotion regulation to effective picture stimuli. Based on the aphasic theory of emotion, it is hypothesized that the startle response will be largest in magnitude in the presence of negative emotional stimuli (Varanasi, Spence, & Lang, 1988).