Answer: SBb
On 1930 the astronomer Edwin Hubble classified the galaxies based on their visual appearance into elliptical, spiral and irregular, being the first two classes the most frequent.
So, according to this classification, the Milky Way is a barred spiral galaxy (SBb in Hubble's notation system) because it has a central bar-shaped structure of bright stars that spans from one side of the galaxy to the other. In addition, its spiral arms seem to emerge from the end of this "bar".
Scientifics considered this, after measuring the the disk and central bulge region of the galaxy, and the conclusion is the Milky Way fulfills these conditions, because is a galaxy that orbits on its same axis and with this rotation its arms are twisted in opposite directions around the mentioned axis.
*Fig is Attached with answer*
Answer:
(a) Weight = Normal Force = 196.2 N
(b) Normal force table on 20 kg box = 294.3 N
Normal force 20 kg box on 10 kg box = 98.1 N
Explanation:
(a) Mass = m = 20 kg g = 9.81 m/s²
Weight = w = mg
w = 20 × 9.81
w = 196.2 N
As the box rests on the table so, normal force (NF) must be equal to the weight of the box.
NF = w = 196.2 N
(b)
m₁ = 20 kg m₂ = 10 kg
total mass = M = 30 kg
Total Weight = W = Mg
= 30 × 9.81
= 294.3 N
As both the boxes rest on the table so, normal force (NF) must be equal to the total weight of the boxes.
NF = W = 294.3 N
Weight of 10 kg box = 10 × 9.81 = 98.1 N
As the 10 kg box is placed on the top of 20 kg box, So 20 kg box must exert a normal force that is equal to the weight of 10 kg box.
Normal Force = Weight of 10 kg box = 98.1 N
Average speed of the runner is the rate at which the runner covers the total distance. Average speed of the runner in the race is given by,
Average speed = 
Where
Total distance = Distance covered by the runner from initial to final position
Total time = time taken by the runner to cover entire distance
Instantaneous speed is the speed of the runner at the particular moment in the given time. Instantaneous speed is given by,
Instantaneous speed = 
x = position of the runner at time t
t = time taken to cover distance x
Hence, Average speed and instantaneous speed are different for a runner running in the race.
Answer:
156.67 m/s
0.45676 times the speed of sound
Explanation:
Distance from the ground = 23.5 km = 23500 m
Time taken by the blast waves to reach the ground = 
Spedd of the wave would be

The velocity of the blast wave is 156.67 m/s
v = Velocity of sound = 343 m/s

The blast wave is 0.45676 times the speed of sound
Answer:
c. 1.5 s
Explanation:
i had this and i got it right