Answer:
Explanation:
The ball will rise decreasing its speed until it reaches the highest point where its speed will be zero. From this point the tennis ball will begin to fall again, in the free fall the tennis ball will gain speed but now in the opposite direction. When it returns to the same point where it was launched, its speed will be the same as the one that was launched but with the opposite sign.
We can check this using the equation:
where 
ang h is the height, but because the ball returns to the same point where it started, h =0
then
the initial and final velocity will be the same in number, but we know that the ball is going in the opposite direction, so the final velocity must have the opposite sign from the initial velocity
so if ,
Answer: 
Explanation:
The mean free path 
of an atom is given by the following formula:
(1)
Where:
is the Universal gas constant
is the absolute standard temperature
is the diameter of the helium atom
is the Avogadro's number
absolute standard pressure
Knowing this, let's find from (1), in order to find the radius 
of the helium atom:
(2)
(3)
(4)
If the radius is half the diameter:
(5)
Then:
(6)
(7)
However, we were asked to find this radius in nanometers. Knowing 
:
(8)
Finally:
This is the radius of the helium atom in nanometers.
Answer:
When direct experimentation is not possible, scientists modify the scientific method. In fact, there are probably as many versions of the scientific method as there are scientists! ... If the experiment works and the data is analyzed you can either prove or disprove your hypothesis.
Explanation:
Answer:
20%
Explanation:
Efficiency of an engine is a ratio in percentage of the work done to the energy intake of the engine.
η=(q₁-q₂)/q₁×100%
η is efficiency, q₁ is the energy intake, q₂ is energy wasted.
the information provided is:
energy intake = 400 j
work done = 80 j = (400-320) =q₁-q₂
energy wasted =320 j
η= 80/400×100%
=20%
Answer:
I'm not sure but, this video's pretty cool: gestyy.com/eyRkH2
Explanation:
pretty scary gameplay
