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.)
<u>Answer</u>
1/4
<u>Explanation</u>
half life = 15 years
decay period = 30 years
The number of half-lives = 30 ÷ 15
= 2 half lives
1 ⇒(<em>after 1st half life</em>) ⇒ 1/2 ⇒ (<em>after 2nd half life</em>) ⇒ 1/4
The fraction that remained is 1/4.
Answer:
That people are motivated by a series of five universal needs.
Explanation:
I think most likely the answer is the first one. meeting other students. if not then maybe the second one, highly motivated.
Answer:
709.93 kg/m³
Explanation:
Density: This can be defined as the ratio of the mass of a body to the volume of that body. The S.I unit of density is kg/m³
From the question above,
D = m/v.............................. Equation 1
Where D = density, m = mass, v = volume.
Note: The volume of the liquid is equal to the volume of the height occupied by the liquid in the container
Since the tank is cylindrical,
v = πr²h........................ Equation 2
Where r = radius of the the tank, h = height of the liquid in the tank
Substitute equation 2 into equation 1
D = m/(πr²h)............... Equation 3
Given: m = 14014 kg, r = 1.35 m, h = 3.45 m, π = 3.14
Substitute into equation 3
D = 14014/(3.14×1.35²×3.45)
D = 14014/19.74
D = 709.93 kg/m³