Answer: From the moment the first gas cloud begins to compress until the star is formed and glows like the Sun, the process of star creation takes around a million years. Planets and other objects circle the central star using the remaining material from the star's formation.
Explanation:
Answer:
The speed is
.
(a) is correct option.
Explanation:
Given that,
Potential difference 
Speed 
If it were accelerated instead
Potential difference 
We need to calculate the speed
Using formula of initial work done on proton

We know that,


Put the value into the formula

....(I)
If it were accelerated instead through a potential difference of
, then it would gain a speed will be given as :
Using an above formula,

Put the value of 



Hence, The speed is
.
For rectilinear motions, derived formulas all based on Newton's laws of motion are formulated. The equation for acceleration is
a = (v2-v1)/t, where v2 and v1 is the final and initial velocity of the rocket. We know that at the end of 1.41 s, the rocket comes to a stop. So, v2=0. Then, we can determine v1.
-52.7 = (0-v1)/1.41
v1 = 74.31 m/s
We can use v1 for the formula of the maximum height attained by an object thrown upwards:
Hmax = v1^2/2g = (74.31^2)/(2*9.81) = 281.42 m
The maximum height attained by the model rocket is 281.42 m.
For the amount of time for the whole flight of the model rocket, there are 3 sections to this: time at constant acceleration, time when it lost fuel and reached its maximum height and the time for the free fall.
Time at constant acceleration is given to be 1.41 s. Time when it lost fuel covers the difference of the maximum height and the distance travelled at constant acceleration.
2ax=v2^2-v1^2
2(-52.7)(x) = 0^2-74.31^2
x =52.4 m (distance it covered at constant acceleration)
Then. when it travels upwards only by a force of gravity,
d = v1(t) + 1/2*a*t^2
281.42-52.386 = (0)^2+1/2*(9.81)(t^2)
t = 6.83 s (time when it lost fuel and reached its maximum height)
Lastly, for free falling objects, the equation is
t = √2y/g = √2(281.42)/9.81 = 7.57 s
Therefore, the total time= 1.41+6.83+7.57 = 15.81 s
11. B
12. A
13. D
14. The ball burnt off energy while rolling, it lost potential energy and couldn't go as high.
Answer:
atm
Explanation:
The pressure at the bottom of any liquid column is equal to product of density of the liquid , gravitational acceleration constant (g) and height of the water column
Thus, 
Substituting the given values, we get -
kg/m3
m/s^2
meters
atm