A light year is a unit of distance. It is a distance that light can travel in a years time which is six trillion miles. It is used to measure the distances in space. To take one example, the distance to the next nearest big galaxy, the Andromeda Galaxy, from earth is 21,000,000,000,000,000,000 km.
Do you understand it? <span />
Answers:
a) 
b) 
Explanation:
a) Since we are told the satellites circle the space station at constant speed, we can assume they follow a uniform circular motion and their tangential speeds
are given by:
(1)
Where:
is the angular frequency
is the radius of the orbit of each satellite
is the period of the orbit of each satellite
Isolating
:
(2)
Applying this equation to each satellite:
(3)
(4)
(5)
(6)
(7)
(8)
Ordering this periods from largest to smallest:

b) Acceleration
is defined as the variation of velocity in time:
(9)
Applying this equation to each satellite:
(10)
(11)
(12)
(13)
(14)
(15)
Ordering this acceerations from largest to smallest:

D. It is personal in style.
Answer:
option C
Explanation:
given,
force act on west = 20 lb
force act at 45° east of north = 80 lb
magnitude of force = ?
∑ F y = 80 cos 45⁰
F y = 56.57 lb
magnitude of forces in x- direction
∑ F x = -20 + 80 sin 45⁰
= 36.57 lb
net force
F = 
F = 
F = 67.36 lb≅ 67 lb
hence, the correct answer is option C