Q:If a closed rigid wall container filled with 20 gm of He moving at a constant speed of 10 m/sec is stopped abruptly to stand still, find the increment in temperature of this He sample.
My question regarding this problem :
- when kinetic energy increases , velocity increases and therefore , temp also increases . Now , in the above Q . If the container is put to a stop after some time , how can there be an increment in temperature since the molecules speed would decrease now. Therefore , their temp should decreases and so should kinetic energy ?
Theory 1:Does the Q mean to say the increment in temperature during the time it was travelling or after the time it was put to stop.
Theory 2:Also , I read online about this Q. It says that my thinking was wrong and what the Q means to say is that when the container is put to stop. There will be collision inside the container which causes the increase in temperature.
Below is how I solved:
Using first law of thermodynamics,
I found kinetic energy which has to be W or macroscopic work done. Then , we have q and $\delta$E left.
q must be 0 since it is a closed container. Therefore , in end . We just equate W and $\delta E$.
Main Q is that which theory is right and is my method of solving above correct ?