Given:
Temperature of water, 
= 
=273 +(-6) =267 K
Temperature surrounding refrigerator, 
= 
=273 + 21 =294 K
Specific heat given for water, 
= 4.19 KJ/kg/K
Specific heat given for ice, 
= 2.1 KJ/kg/K
Latent heat of fusion, 
= 335KJ/kg
Solution:
Coefficient of Performance (COP) for refrigerator is given by:
Max 
= 
= 
= 9.89
Coefficient of Performance (COP) for heat pump is given by:
Max 
= 
= 10.89
Answer:
14.52 minutes
<u>OR</u>
14 minutes and 31 seconds
Explanation:
Let's first start by mentioning the specific heat of air at constant volume. We consider constant volume and NOT constant pressure because the volume of the room remains constant while pressure may vary.
Specific heat at constant volume at 27°C = 0.718 kJ/kg*K
Initial temperature of room (in kelvin) = 283.15 K
Final temperature (required) of room = 293.15 K
Mass of air in room= volume * density= (4 * 5 * 7) * (1.204 kg/m3) = 168.56kg
Heat required at constant volume: 0.718 * (change in temp) * (mass of air)
Heat required = 0.718 * (293.15 - 283.15) * (168.56) = 1,210.26 kJ
Time taken for temperature rise: heat required / (rate of heat change)
Where rate of heat change = 10000 - 5000 = 5000 kJ/hr
Time taken = 1210.26 / 5000 = 0.24205 hours
Converted to minutes = 0.24205 * 60 = 14.52 minutes
Answer:
Velocity of ball B after impact is 
and ball A is 
Explanation:
= Initial velocity of ball A
= Initial velocity of ball B = 0
= Final velocity of ball A
= Final velocity of ball B
= Coefficient of restitution = 0.8
From the conservation of momentum along the normal we have
Coefficient of restitution is given by
Adding the above two equations we get
From the conservation of momentum along the plane of contact we have
Velocity of ball B after impact is and ball A is .
Explanation:
≈4.8
There really isn't an elegant way to express it. Just plug and chug for irrationals raised to other irrationals.
