Why is the weight of an object more on Earth than the Moon

The place you get your hair cut has two nearly parallel mirrors 6.00 m apart. as you sit in the chair, your head is 2.00 m from the nearer mirror. looking toward this mirror, you first see your face and then, farther away, the back of your head. (the mirrors need to be slightly nonparallel for you to be able to see the back of your head, but you can treat them as parallel in this problem.) how far away does the back of your head appear to be?

Which of the following are guidelines to follow for obtaining accurate observations

Mechanical energy is when the amount of kinetic and potential energies added together remains the same. conserved created lost