Answer:
15m/s
Explanation:
add the two speeds and divide by 2
10+20=30
30/2=15
Heat is the answer but I need to use 20 characters to post :)
In physics, work is defined as the total energy when an object is moved to a certain displacement by the application of external force. It is calculated by the expression W = Fd. For this case, the displacement is apparently zero, then there is no work in the system above.
Thermal energy is the answer
