Really, Gundy ? ! ?
The formula for the car's speed is given and discussed in the box. The formula is
v = √(2·g·μ·d)
Then they <em>tell</em> you that μ is 0.750 , and then they <em>tell</em> you that d = 52.9 m . Also, everybody knows that 'g' is gravity = 9.8 m/s² .
They also tell us that the mass of the car is 1,000 kg, and they tell us that it took 3.8 seconds to skid to a stop. But we already <em>have</em> all the numbers in the formula <em>without</em> knowing the car's mass or how long it took to stop. The police don't need to weigh the car, and nobody was there to measure how long the car took to stop. All they need is the length of the skid mark, which they can measure, and they'll know how fast the guy was going when he hit the brakes !
Now, can you take the numbers and plug them into the formula ? ! ?
v = √(2·g·μ·d)
v = √( 2 · 9.8 m/s² · 0.75 · 52.9 m)
v = √( 777.63 m²/s²)
v = 27.886 m/s
Rounded to 3 digits, that's <em>27.9 m/s </em>.
That's about 62.4 mile/hour .
Answer:
c. the volume of the part of the ship that lies below the water's surface.
Explanation:
As stated in the problem, Archimedes' Principle tells us that that buoyant force on an object is equal to the weight of fluid it displaces. The volume of water that a ship displaces is the volume it occupies below the surface.
Every element is able to be recognized individually in many different ways. A very easy and common way is using light absorption also known as spectroscopy. Every atom has electrons, and these electrons like to stay in their lowest-energy configuration. However, when photons collide with an electron it can increase it to a higher energy level.. This is absorption, and each element’s electrons absorb light at specific wavelengths related to the difference between energy levels in that atom. But the electrons want to return to their original levels, so they don’t hold onto the energy for long. When they emit the energy, they release photons with exactly the same wavelengths of light that were absorbed in the first place. An electron can release this light in any direction, so most of the light is emitted in directions away from our line of sight. Therefore, a dark line appears in the spectrum at that particular wavelength.
Because the wavelengths at which absorption lines occur are unique for each element, astronomers can measure the position of the lines to determine which elements are present in a target. The amount of light that is absorbed can also provide information about how much of each element is present.
