00:01
So this question belongs to the thermal properties of matter in which we have given power of the drilling machine p 10 kilowatt that is equal to 10 into 10 to the power 3 watt and mass of the aluminum block to board which is equals to 8 .0 kg and we have to determine how much is the rise in the temperature that is delta t in the time small t equals to 2 .5 minute that is equal to 150 seconds.
00:31
Second, okay, 150 second.
00:36
And we have given that 50 % of the power is utilized, so efficiency it is equals to 50%.
00:45
Or this is equal to 0 .50 and specific heat of the aluminum c, it is equals to 0 .91 joule per gram and per kelvin.
00:58
Okay, so now we can calculate the total energy.
01:03
Of the drilling machine e, this is equal to power multiplied by time t, so power which is 10 into 10 to the power 3 and time t is 15 seconds, so energy total which is consumed, it is equals to 1 .5 multiplied by 10 to the power 6 jule.
01:19
Now since efficiency is 50%, that is 50 % power is utilized to heat the machine itself, so hence useful energy delta q becomes equals to 0 .50 multiplied by e, so this is equal to 0 .50, mudplared by 1 .5 into 10 to the power 6 jule.
01:38
So this is equal to 7 .5 mudplared by 10 to the power 5 jule.
01:43
So this much of heat is utilized to heat up the machine itself...