The temperature inside the copper rod varies linearly with the distance from the hot end of the rod. This means that we can find the temperature at 23 cm (let's call it 'point A') from the cool end by solving a linear proportion.
The temperature difference between the two ends of the rod is

and this corresponds to a length of 81 cm. Therefore, we can write:

from which we find

This is not the final answer actually; this is the temperature difference between the cool end and point A. So, the temperature at point A is
When you exert a force on the coin, it will accelerate. If you push the coin and it moves at a constant velocity, the friction force must be equal to the force that you are exerting. This is an example of a balanced force. When the net force is greater than 0 N, the is an unbalanced force.
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E=(mV^2)/2
m=1000kg, V=20m/s
then, E=(1000kg*(20m/s)^2)/2
E=(1000*400)/2 J = 200000J