<span>In assumption that there were two scientists who used
different measurement systems in their research. The problems that might arise
if they shared their data is obviously and primarily error. Errors are
recognized and one element in every measure, system and quantity. Error was
already even present in the measurement system alone a scientist used and it
will furthermore aggregate, when these two different scales are combined the
more error escalates in the process. There are two types: random and systematic
error. </span>
Answer: 1.39 s
Explanation:
We can solve this problem with the following equations:
(1)
(2)
Where:
is the length the steel wire streches (taking into account 1mm=0.001 m)
is the length of the steel wire before being streched
is the force due gravity (the weight) acting on the pendulum with mass 
is the transversal area of the wire
is the Young modulus for steel
is the period of the pendulum
is the acceleration due gravity
Knowing this, let's begin by finding
:
(3)
Where
is the diameter of the wire
(4)
(5)
Knowing this area we can isolate
from (1):
(6)
And substitute
in (2):
(7)
(8)
Finally:

Answer:
442.36038 m or 1451.31362 ft
Explanation:
= Initial pressure = 30.15 inHg
= Final pressure = 28.607 inHg
= Density of air = 0.075 lb/ft³



Density of mercury = 13560 kg/m³
g = Acceleration due to gravity = 9.81 m/s²
Difference in pressure is given by

The height of the building is 442.36038 m or 1451.31362 ft
1 newton-meter is 1 Joule, the unit of work and energy.
The answer would be:
B. Chlorine, iodine and Fluorine
Barium has 2 valence electrons. To satisfy the BaX₂ , this would mean that Barium will need to give one of each of its electrons. The elements that need 1 electron would be those that have 7 valence electrons to complete the octet. These elements would fall in group 7 or halogens. Chlorine, iodine and fluorine are all in Group 7, so this would be the best choice.