A 10 kW drilling machine is used to drill a bore in a small aluminium block of mass 8.0 kg. How much is the rise in temperature of the block in 2.5 minutes, assuming 50% of power is used up in heating the machine itself or lost to the surroundings. Specific heat of aluminium = 0.91 J g –1 K –1 .
Answers
Answered by
53
use conservation of energy theorem
heat lose=heat gain
because power used by machine =10kw
but we know
heat=power x time
=10000 w x{ (2.5 ) x 60}sec
=1500000 w =1500 kj
now heat lose at drilling time =1500 x50/100= 750 kj
now
750=mSdT
where S is specific heat of Al and dT is temperature change
750000j =8000g x (0.91jg-1k-1) x dT
dT=103.02 K
hence temperature rise 103.02 K
heat lose=heat gain
because power used by machine =10kw
but we know
heat=power x time
=10000 w x{ (2.5 ) x 60}sec
=1500000 w =1500 kj
now heat lose at drilling time =1500 x50/100= 750 kj
now
750=mSdT
where S is specific heat of Al and dT is temperature change
750000j =8000g x (0.91jg-1k-1) x dT
dT=103.02 K
hence temperature rise 103.02 K
Answered by
1
Answer:
103°C
Explanation:
refer attachment.
hope this helps :)
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