Answer:
20 degrees.
Explanation:
this is my answer hope that I will help you
Separation of light into different color is called "dispersion". Rainbow, comes from refraction and reflection of sunlight, in the falling raindrops, which means that that the refractive index of water depends on the wavelength of light.
A positive charged atom has lost electrons.
Electrons are present in the outer shell of an atom, loosely bond to the nucleus, the only binding force on the electrons is the electric force, while the protons are inside the nucleus, and tightly bond to the nucleus by nucleus binding force, therefore an atom can only be positively charged when it loose electron from the shall.
Answer:
Part(a): The average acceleration is 
during the first 6s.
Part(b): The average acceleration from 6s to 8s is zero.
Explanation:
Part(a):
The average acceleration is defined as the rate at which velocity is changing with respect to time. So if '
', '
' and '
' represents the initial velocity, final velocity, and average acceleration of a particle, then mathematically
where '
' is the time taken by the particle to achieve the velocity '' starting from initial velocity ''
Given in the problem, 
.
So the average acceleration() during the first 6 s will be
Part(b):
During the time between 6 s to 8 s, as mentioned in the problem, the sprinter maintains the constant velocity. So the average acceleration during this time interval will be zero.
Its a type of phase change and it is melting.
