Assuming north as positive direction, the initial and final velocities of the ball are:
(with negative sign since it is due south)
the time taken is
, so the average acceleration of the ball is given by
And the positive sign tells us the direction of the acceleration is north.
Give the other person brainest I was gonna answer but found no need if you get me
Answer : The energy of one photon of hydrogen atom is, 
Explanation :
First we have to calculate the wavelength of hydrogen atom.
Using Rydberg's Equation:
Where,
= Wavelength of radiation
= Rydberg's Constant = 10973731.6 m⁻¹
= Higher energy level = 3
= Lower energy level = 2
Putting the values, in above equation, we get:
Now we have to calculate the energy.
where,
h = Planck's constant = 
c = speed of light = 
= wavelength = 
Putting the values, in this formula, we get:
Therefore, the energy of one photon of hydrogen atom is,
Answer:
velocity changes over time.
