I think it's 3. within an outer arm
        
                    
             
        
        
        
Answer:
7.45 s.
Explanation:
Given:
h = 68.1 m
vi = 0 m/s
vf = 42.4 m/s
g = 9.81 m/s^2
Using,
h = vi*t +1/2*(a*t^2)
68.1 = 1/2 * (9.81*t^2)
t = sqrt((68.1*2)/9.81)
= 3.726 s.
Total time of flight = 2*t
= 2 * 3.726
= 7.45 s.
 
        
                    
             
        
        
        
An 'alpha particle' is the same thing as the nucleus of a helium atom ... 
a little bundle made of 2 protons and 2 neutrons.
A 'beta' particle is an electron.
The mass of an alpha particle is more than 7,000 times the mass of 
an electron, so it certainly takes more energy to get it moving.
        
                    
             
        
        
        
400m in 32sec: (400/32)>12.5meters per second>
(12.5)(60)(60)(1/1000)=45km per hour
Constant speed would mean that the two forces are equivalent
        
             
        
        
        
There are different forces acting on an object like nuclear force , gravitational force...plus external forces like friction and other..
net sum of all these is resultnat