Suppose the satellite loses mechanical energy at the average rate of 2.0 ✕ 105 J per orbital revolution. Adopt the reasonable approximation that the satellite's orbit becomes a "circle of slowly diminishing radius."

can be answered using momentum.

momentum = p

p1= mass1 * velocity1

p1 = p2

therefore

p1 = 6kg * 4m/s

p1 = 24kgm/s

p2=m2 * v2

24 kgm/s = 7kg * v2

v2 = 24 kgm/s / 7kg

v2= 3.42 m/s

friction

explanation:

they us to move forward and backwards

one "light year" is the distance that light travels, through vacuum, in one julian year.   that's 365.25 days, of 24 hours each.