One can simply find the frictional force acting on an object using this equation:
(Ffrict<span> = μ•F</span>norm<span>)
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The process of determining the value of the individual forces acting upon an object involve an application of Newton's second law (Fnet=m•a) and an application of the meaning of the net force. If mass (m) and acceleration (a) are known, then the net force (Fnet) can be determined by use of the equation.
<span>Fnet = m • a</span>
If the numerical value for the net force and the direction of the net force is known, then the value of all individual forces can be determined.
The magnitude of the electric current is directly proportional to the "Electric Charge" <span>of the electric field.
Hope this helps!</span>
Answer:
4589.05 year
Explanation:
The relation of activity is given by
we have given
Half life 
We know that half life 

So 



solution:
We know v0 = 0, a = 9.8, t = 4.0. We need to solve for v
so,
we use the equation:
v = v0 + at
v = 0 + 9.8*4.0
v = 39.2 m/s
Now we just need to solve for d, so we use the equation:
d = v0t + 1/2*a*t^2
d = 0*4.0 + 1/2*9.8*4.0^2
d = 78.4 m