Answer:
Option (3)
Explanation:
Nicolaus Copernicus was an astronomer from Poland, who was born on the 19th of February in the year 1473. He played a great role in the field of modern astronomy.
He was the person who contributed to the heliocentric theory. This theory describes the position of the sun in the middle of the universe, and all the planets move around the sun. This theory was initially not accepted, and after about a century it was widely accepted.
This theory describes the present-day motion of the planets around the sun in the solar system. This theory replaced the geocentric theory.
Thus, the correct answer is option (3).
Answer:
V (initial vertical velocity) = 45.4 sin 31.2 = 23.52 m/s
1/2 m V^2 = m g h conservation of energy
h = V^2 / (2 g) = 23.52^2 / 19.6 = 28.2 m max height
Check:
t = 28.2 / 9.8 = 2.88 sec time to reach max height
h = 23.52 * 2.88 - 1/2 g 2.88^2 = 27.1 m
Answer:
The number of protons can be found by looking at the atomic number
Explanation:
Its at the very top of the little element box
That Energy Cannot Be Created Nor Destroyed
Lifting a mass to a height, you give it gravitational potential energy of
(mass) x (gravity) x (height) joules.
To give it that much energy, that's how much work you do on it.
If 2,000 kg gets lifted to 1.25 meters off the ground, its potential energy is
(2,000) x (9.8) x (1.25) = 24,500 joules.
If you do it in 1 hour (3,600 seconds), then the average power is
(24,500 joules) / (3,600 seconds) = 6.8 watts.
None of these figures depends on whether the load gets lifted all at once,
or one shovel at a time, or one flake at a time.
But this certainly is NOT all the work you do. When you get a shovelful
of snow 1.25 meters off the ground, you don't drop it and walk away, and
it doesn't just float there. You typically toss it, away from where it was laying
and over onto a pile in a place where you don't care if there's a pile of snow
there. In order to toss it, you give it some kinetic energy, so that it'll continue
to sail over to the pile when it leaves the shovel. All of that kinetic energy
must also come from work that you do ... nobody else is going to take it
from you and toss it onto the pile.
