Answer:
<em>In the observational method, the hypothesis is constructed to explain the observations. A simple one may be a generalization of the observations. A more complex hypothesis may postulate a relationship between the events, and may even be used to predict other observations.</em>
Every material in the world can be defined in terms of how well it conducts electricity. Certain things, such as cold glass, never conduct electricity. They're known as insulators. Materials which do conduct electricity, like copper, are called conductors. In the middle are materials known as semiconductors, which don't conduct as well as conductors, but can carry current. Last, are materials called superconductors, which when brought down to very low temperatures turn into superhighways of current -- they conduct electricity without any resistance whatsoever.
Answer:
(a)-24 ft/s
(b)-16.8 ft/s
(c)-16.16 ft/s
(d) -16 ft/s
Explanation:
The initial velocity, v=48 ft/s
(a)
The average velocity when t=2 and 0.5 seconds later hence t=2.5 is given by
![\frac {f(2)-f(2.5)}{2-2.5}=\frac {[48(2)-16(2)^{2}]-[48(2.5)-16(2.5)^{2}]}{2-2.5}=\frac {32-20}{-0.5}=-24 ft/s](https://tex.z-dn.net/?f=%5Cfrac%20%7Bf%282%29-f%282.5%29%7D%7B2-2.5%7D%3D%5Cfrac%20%7B%5B48%282%29-16%282%29%5E%7B2%7D%5D-%5B48%282.5%29-16%282.5%29%5E%7B2%7D%5D%7D%7B2-2.5%7D%3D%5Cfrac%20%7B32-20%7D%7B-0.5%7D%3D-24%20ft%2Fs)
(b)
The average velocity when t lasts 0.05 second then
t=2 and t=2.05 is given by
![\frac {f(2)-f(2.05)}{2-2.05}=\frac {[48(2)-16(2)^{2}]-[48(2.05)-16(2.05)^{2}]}{2-2.5}=\frac {32-31.16}{-0.05}=-16.8 ft/s](https://tex.z-dn.net/?f=%5Cfrac%20%7Bf%282%29-f%282.05%29%7D%7B2-2.05%7D%3D%5Cfrac%20%7B%5B48%282%29-16%282%29%5E%7B2%7D%5D-%5B48%282.05%29-16%282.05%29%5E%7B2%7D%5D%7D%7B2-2.5%7D%3D%5Cfrac%20%7B32-31.16%7D%7B-0.05%7D%3D-16.8%20ft%2Fs)
(c)
The average velocity when t=2 and lasts 0.01 s then t=2.01 then is determined by
![\frac {f(2)-f(2.01)}{2-2.01}=\frac {[48(2)-16(2)^{2}]-[48(2.01)-16(2.01)^{2}]}{2-2.01}=\frac {32-31.8384}{-0.01}=-16.16 ft/s](https://tex.z-dn.net/?f=%5Cfrac%20%7Bf%282%29-f%282.01%29%7D%7B2-2.01%7D%3D%5Cfrac%20%7B%5B48%282%29-16%282%29%5E%7B2%7D%5D-%5B48%282.01%29-16%282.01%29%5E%7B2%7D%5D%7D%7B2-2.01%7D%3D%5Cfrac%20%7B32-31.8384%7D%7B-0.01%7D%3D-16.16%20ft%2Fs)
(d)
As the intervals get small, that is to imply from 0.05 s later to 0.01 s later as seen in parts a to c, the values are getting small and closer to 16 hence the instantaneous velocity at t=2 is -16 ft/s
Answer:
u = 9.2 m/s
Explanation:
Second equation of motion:
s = u t + 0.5 a t²
The time in which book would fall 35.4 m downwards is:
Initial velocity is zero in vertical direction.
35.4 = 0 + 0.5 (9.8)t²
⇒ t² = 7.22 ⇒t = 2.68 s
The horizontal distance covered by Henrietta in (7.00 s+ 2.68 s):
x = 2.55 m/s × 9.68 s = 24.684 m
The initial velocity with which the book must be thrown in order for Henrietta to catch.
24.684 m = u ( 2.68 s)
u = 9.2 m/s
Answer:
38400 atoms
Explanation:
The half - life is the time taken for a radioactive material to decay by half. When the half-life time elapses, a material becomes halved.
Since the half-life is 12yrs;
number of atoms now = 2400atoms
Unknown:
Number of atoms in the sample 48yrs ago;
Solution:
In 48yrs, we have 4 half-life counts:
Last 12yrs;
2(2400) = 4800atoms
Last 24yrs
2(4800) = 9600 atoms
Last 36yrs
2(9600) = 19200 atoms
Last 48yrs
2(19200) = 38400 atoms
