How would your energy accounting be different in each of these two alternative definitions of the system?

The coefficient of friction is a number that represents the resistance to sliding between two in contact with one another.

What distance does a car travel as its speed changes from 0 to 20 m/s in 17 s at constant acceleration?

Scientists follow specific processes in order to determine valid explanations and conclusions from observations. david observed strange lights in the sky above his home outside of roswell, new mexico. the only explanation that makes sense to him is that there are ufos in the area. what should david do next to verify his explanation?