Physical change 1 is the answer
Work of the force = 10 N
Time required for the work = 50 sec
Height = 7 m
We are given with the value of work and time in the question.
Substitute the values in the formula of power and then you'll get the power required.
We know that,
w = Work
p = Power
t = Time
By the formula,
Given that,
Work (w) = 7 m = 70 Joules
Time (t) = 50 sec
Substituting their values,
p = 70/50
p = 1.4 watts
Therefore, the power required is 1.4 watts.
Hope it helps!
Force = mass x acceleration
15 = mass x 4
Mass = 15/4
Mass = 3.75 Kg
Answer:
Charge on each metal sphere will be 
Explanation:
We have given number of electron added to metal sphere A 
As both the spheres are connected by rod so half -half electron will be distributed on both the spheres.
So electron on both the spheres 
We know that charge on each electron 
So charge on both the spheres will be equal to 
So charge on each metal sphere will be equal to 
Explanation:
Since, it is mentioned the there occurs no change in the temperature. This also means that there will occur no change in thermal energy of the system.
Hence,
= 0. And, as
= 0 then there will be no work involved. This means that total energy added to the house will return to the outside air as heat.
Therefore,
Q = -(19000 J + 2000 J)
= -21000 J
or, |Q| = 21000 J
Thus, we can conclude that the magnitude of the energy transfer between the house and the outside air is 21000 J.