A 10kw drilling machine is used for 5 minutes to bore a hole in an aluminium block of mass `10xx10^(3)kg`. If 40% of the work done is utilised to raise the temperature of the block, then find the raise in temperature of the aluminium block?
(Specific heat of Aluminium `=0.9 Jkg^(-1)k^(-1)`)

Explanation

Work done by the drilling machine in 5 min
W=power x time `=10xx10^(3)xx5xx60=3xx10^(6)J`
The energy utilised to rise the temperature of the
block `=40% "of" W=3xx10^(6)xx(40)/(100)=12xx10^(5)J`
Heat gained by aluminimum block=
mass xx specific heat xx increase in temperature
`12xx10^(5)=(10xx10^(3))xx0.9xxDeltat`
`therefore Deltat=(12xx10^(5))/(0.9xx10^(4))=133.3^(@)C`