Answer:
(a) Time t = 16.46 sec
(b) Time t =13.466 sec
(c) Deceleration = 
Explanation:
(a) As the train starts from rest its initial velocity u = 0 m/sec
Acceleration 
Final speed v = 80 km/hr

From first equation of motion v =u+at
So 
(b) Now initial speed u = 22.22 m/sec
As finally train comes to rest so final speed v=0 m/sec
Deceleration 
So 
(c) We have given that initial velocity = 80 km/hr = 22.22 m/sec
Final velocity v = 0 m/sec
Time t = 8.30 sec
So acceleration is given by

As acceleration is negative so it is a deceleration
The statement that best describes the production of energy in the Sun is nuclei with less mass combine to form nuclei with more mass in the Sun’s core and release energy.
<h3>How is energy produced in the sun?</h3>
Sun is a major source of renewable energy to the Earth. This energy serves various purposes by living organisms.
However, the energy is generated as a result of nuclear fusion, which is the combination of smaller particles to form a larger one.
Therefore, the statement that best describes the production of energy in the Sun is nuclei with less mass combine to form nuclei with more mass in the Sun’s core and release energy.
Learn more about energy at: brainly.com/question/1932868
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<span>it will be changed by changing the medium of the wave</span>
Answer:
when the direction of the Current changes.
Explanation:
Electromagnet refers to an iron ore wrapped around with a coil of wire, in presence of electric current. As it acts like a magnet, when current is passed through it.
The north & south poles of magnetic fields produced by such magnet, change with direction of current passed through it.