Question

A rigid container equipped with a stirring device contains 2.8 kg of motor oil. Determine the rate of specific energy increase when heat is transferred to the oil at a rate of 1 W, and 1.5 W of power is applied to the stirring device. (Round the final answer to one decimal place.)

Answer 1

Answer:

Rate of change of specific energy will be $=\frac{2.5}{2.8}=0.8928j/kgsec$                      

Explanation:

We have given mass of the motor oil m = 2.8 kg

Heat is transferred to the oil at a rate Q = 1 W

Power supply by stemming device  $W=-1.5Watt$

Applying first law to the device

$Q=W+dU$

$1=-1.5+dU$

$dU=2.5$

Rate of change of specific energy will be $=\frac{2.5}{2.8}=0.8928j/kgsec$