Answer:
Associations Clusters
Explanation:
There is three basic type of clusters, globular clusters, open clusters, associations clusters. Associations cluster consist of younger stars that is younger than globular and open clusters stars.
Answer:
The angular velocity is 
Explanation:
From the question we are told that
The mass of each astronauts is 
The initial distance between the two astronauts 
Generally the radius is mathematically represented as 
The initial angular velocity is 
The distance between the two astronauts after the rope is pulled is 
Generally the radius is mathematically represented as 
Generally from the law of angular momentum conservation we have that

Here
is the initial moment of inertia of the first astronauts which is equal to
the initial moment of inertia of the second astronauts So

Also
is the initial angular velocity of the first astronauts which is equal to
the initial angular velocity of the second astronauts So

Here
is the final moment of inertia of the first astronauts which is equal to
the final moment of inertia of the second astronauts So

Also
is the final angular velocity of the first astronauts which is equal to
the final angular velocity of the second astronauts So

So

=> 
=> 
=> 
=> 
The word "static" would be known to be friction as air rushing against an airplane
Let's break the question into two parts:
1) The force needed in Ramp scenario.
2) The effort force needed in the lever scenario.
1. Ramp Scenario: In an incline, the only component of cart's weight(
mg) that is in the direction of motion is
. Therefore the effort force in this case must be equal or greater than
.
Now we need to find

.

is the angle between the incline of the ramp and the ground.
Since the height is
5m and the length of the ramp is
8m, 
would be
5/8 or 0.625. Now that you have

, mutiple it with
mg.
=> m*g*

= 20 * 10 * 5 / 8. (Taking g = 10 m/s² for simplicity) = 125N
Therefore, the minimum Effort force you would require in this case is
125N.
2. Lever Scenario:
Just apply "moment action" in this case, which is:


= ?

= mg = 20 * 10 = 200N

= 10m

= 1m
Plug-in the values in the above equation:

= 200/10=
20NAs 20N << 125N, the best choice is to use lever.
Answer: Due that we don't know the initial speed after hitting the ball, we are going to accept that the ball goes up for half of the time and then falls during other half part, that is 3.0 seconds each. Then we know that ball's movement is ruled by the acceleration of gravity formula, as follows: H = Vi * T + 1/2 * g * T^2 V = Vi + g * T where: H is height, Vi initial speed, g gravity acceleration and T time When we only consider the second half of the trajectory, we have that initial speed at the top of that movement is zero, because ball goes up till top, where stops and starts to go down, so : H = 0 * 3 + 1/2 * 32 * 3^2 = 144 ft. So the height of the pop-up is 144 feet.