Dubnium is a synthetic element ... Number 105. It can be created
in a laboratory but it's not found in nature.
Fifteen (15) different isotopes of Dubnium have been created. They all
have 105 protons in the nucleus of every atom, but they have anywhere
from 256 to 270 neutrons in each nucleus.
The most stable isotope of Dubnium is ²⁶⁸Db , with 163 neutrons in the
nucleus. That form of Dubnium atom has a 50-50 chance of surviving
for around 28 hours before it falls apart.
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The six commonly recognised metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium....
Answer:
-39.2m/s
Explanation:
Using the equation of motion;
v = u + at
Since the ball is thrown upward, the acceleration due to gravity acting on it will be negative, hence a = -g
v = u - gt
Since g = 9.8m/s²
t = 4.0s
u = 0m/s
v = 0 + (-9.8)(4)
v = 0 + (-9.8)(4)
v = -39.2m/s
Hence the speed of the ball before release is -39.2m/s
Answer:
1400 N
Explanation:
Change in momentum equals impulse which is a product of force and time
Change in momentum is given by m(v-u)
Equating this to impulse formula then
m(v-u)=Ft
Making F the subject of the formula then

Take upward direction as positive then downwards is negative
Substituting m with 0.3 kg, v with 2 m/s, and u with -5 m/s and t with 0.0015 s then

Answer:
Install sound absorbers such as foam or acoustical panels
Explanation:
They could install some sound absorbers such as foam or acoustical panels in the walls, floors, and ceiling of the conference room.