Explanation:
Given that,
Wavelength of the light, 
Work function of sodium, 
The kinetic energy of the ejected electron in terms of work function is given by :

The formula of kinetic energy is given by :

Hence, this is the required solution.
Write out what you have which is:
initial velocity
final velocity
Y distance
degree
You do not have :
a
X distance
t
from what you have you can plug into your formulas to get time.
Answer:
280 N
Explanation:
acceleration = v2-v1 / time taken = (2-4 )/ 0.05 = -40 m/s^2 ( neg sign indicates slowing down )
force exerted = ma = 7 kg x -40 m/s^2 = - 280 N ( neg sign means opposite direction of initial velocity )
since the 7 kg ball is slowing down, the direction of force will be opposite of the initial velocity , and it will be 280 N
<span>For precipitation to form, cloud droplets must grow in volume by roughly one million times.
Hope I helped :)</span>
Neon and helium are both gases that fall under the Noble Gases section in the periodic table of elements.
Hope this helped to answer your question. :D