For Newton's second law, the resultant of the forces acting on the book is equal to the product between the mass of the book and its acceleration:
(1)
There are only two forces acting on the book:
- its weight, directed downward: mg
- the force exerted by the hand on the book, of 20 N, directed upward
so, equation (1) becomes
from which we can calculate the book's acceleration, a:
Answer:
Energy resources can be measured. They will include the fossil fuels, geothermal and hydroelectric potential, and increasingly the renewable resources. When the US list is compared to the World it is considered energy Rich. When Japan's list is compared to the world standard it considered energy poor.
A changing technology like nuclear fusion could substantially change the assessment.
Japan does not have any substantial, oil, coal, gas, deposits, while the US does.
Explanation:
Answer:
<em>The athlete will rise 1.10 meters off the ground</em>
Explanation:
<u>Vertical Motion</u>
If an object is launched vertically upwards at an initial speed vo, then it will reach a maximum height given by
The athlete can exert a net force upwards equal to twice his weight. It makes him accelerate upwards at
The speed at the end of his push can be computed by
Replacing the value of a obtained above:
where y is the length of this crouch
This is the initial speed of this vertical launch, thus
(a) According to Newton’s third law, for every action
there is an equal yet opposite reaction. In this case, the cannonball is
affected by 8.0x10^3 newtons in one direction. Now the cannon must also be
affected by the same amount of net force on the opposite direction.
- 8.0x10^3 Newtons (the negative symbol only shows that it
is opposite direction)
(b) We solve this using the formula:
F = m a
8.0x10^3 N = (1.0 kg) a
a = 8,000 m/s^2
<span>With a half-life of 700 million years, U-235 would have had twice as much mass at a time 700 MYA. This would have put the mass at 100kg at that time. Going back another 50 million years would be (50/700) or 1/14 of the half-life, or (1/2 * 1/14), or 1/28 of the total mass. 1/28 of 100kg is 3.57kg, so the amount present at the 750MYA mark would be approximately 103.57kg of U-235.</span>
