Answer:
Explanation:
The acceleration of gravity is 9.8m/s^2.
So to calculate the time it will take to make the ball stop(which btw means the ball now reach its greatest height), use the formula V1=V0+at. V1 is the final velocity(which is 0), V0 is the starting velocity(which is 30m/s), and the a(cceleration) is 9.8m/s^2.
(You can ignore the fact "at" is -30 instead 30, it's because the directions two velocity travel are opposite. )
We can now know the time it takes to make the ball stop just by the gravitational force is about 3 sec.
Use another formula S=1/2at^2, to find out the S(height) is 1/2*9.8*3^2=44.1, which is approximately D.45m .
Answer:

Explanation:
Given data
Force F=2 N
Length L=17 cm = 0.17 m
Spring Constant k=42 N/m
To find
Relaxed length of the spring
Solution
From Hooke's Law we know that

Answer:
yes
Explanation:
because the planet exerts a centripetal force on the meteorold
Answer:
(4.31±0.38) million Solar masses.
Explanation:
The galactic center is the center of the milky way around which the galaxy rotates. It is most likely the location of a supermassive black hole which has a mass of (4.31±0.38) million Solar masses. The location is called Sagittarius A*.
As there is interstellar dust in our line of sight from the Earth infrared observations need to be taken.