Answer:
Explanation:
Use the one-dimensional equation for displacement:
Δx = v₀t + where Δx is the displacement, v₀ is the initial velocity (which is 0 since someone had to be holding the penny still before it was dropped), t is the time it takes to travel a certain distance (which is given as 4 seconds), and a is the acceleration due to gravity which is -9.8 m/s/s. Filling in:
Δx = I'm going to expand this first so you can see how the units work out. First of all, anything times 0 is 0, so what is right in front of the plus sign goes to 0 and I'm going to leave it out. How this looks expanded without doing any of the actual math yet is:
Δx = which makes it apparent that the seconds-squared cancel each other out, leaving us with the meters only. NOW doing the math and rounding to 2 sigfig's even though there's only 1 in the number 4:
Δx = 78 m(the negative would only be used if the question we were answering was how far the penny had to fall, which would then use the negative sign to indicate that the penny is falling to a point that is below th point from which it was released. Since height is a distance measurement, it will never be negative. Keep in mind, asking how far the penny fell is not the same thing in physics as asking how tall the building was that the penny fell from.)
We first calculate for the volume of each of the figure by dividing all together the dimensions of the rectangular prism.
Volume = (10 ft)(3 ft)(3 ft) = 90 ft³
Then, multiply the volume of each prism by 10 to get the total amount of cement that needs to be poured.
Total volume = (90 ft³)(10) = 900 ft³
I believe it is the 2nd one because the ground purifies it over a period of a little while.
ANSWER: How many elements the brothers have discovered
Strong forces:
- are forces holding nucleons together
- are independent of electric charge
- act only over a very short distance
So, correct answer is 4) all of these
Explanation:
The strong force is one of the 4 fundamental forces of nature. It is responsible for holding the nucleons (protons and neutrons) together into the nucleus of the atom.
In fact, the protons inside the nucleus of an atom experience a repulsive, electrostatic force between each other: if this force was not balanced, the protons will simply fly away from each other, and the nucleus would break apart, so no nucleus could exist.
The strong force acts to prevent this effect: the strong force is attractive at such short scales, and it holds the protons and the neutrons together. It is independent of the electric charge: in fact, it acts in the same way on protons and neutrons, being attractive in both cases. Also, the strong force acts only over very short distances, so it acts only inside the nucleus of an atom.
Therefore, all the statements are correct, so the correct option is
4) all of these
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