<h2>
Answer:</h2>
-310J
<h2>
Explanation:</h2>
The change in internal energy (ΔE) of a system is the sum of the heat (Q) and work (W) done on or by the system. i.e
ΔE = Q + W ----------------------(i)
If heat is released by the system, Q is negative. Else it is positive.
If work is done on the system, W is positive. Else it is negative.
<em>In this case, the system is the balloon and;</em>
Q = -0.659kJ = -695J [Q is negative because heat is removed from the system(balloon)]
W = +385J [W is positive because work is done on the system (balloon)]
<em>Substitute these values into equation (i) as follows;</em>
ΔE = -695 + 385
ΔE = -310J
Therefore, the change in internal energy is -310J
<em>PS: The negative value indicates that the system(balloon) has lost energy to its surrounding, thereby making the process exothermic.</em>
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Answer:
B
Explanation:
A solenoid is the wraps of conducting wire wrapped around the metal core .
Answer:
V = 0.32 m /s
Explanation:
Momentum of the man on the sledge along with sledge
= (80+8) x 10 = 880 kg. m/s When the man jumps off the sledge , the velocity of the sledge will remain intact at 10 m/s
When the sledge hits the boulder and bounces back the momentum of the sledge - boulder system will remain conserved .
change in momentum of sledge = 8 x (10 +6 )
= 128 kg m/s
Change in the momentum of boulder
= 400 V -0
= 400V
400V = 128
V = 0.32 m /s
