The mass of a radioactive element at time t is given by
where
is the mass at time zero, while 
is the half-life of the element.
In our problem,
, t=121.0 s and 
, so we can find the initial mass :
where
In our problem,
The speed of all electromagnetic waves is 3. 00 × 108 meters per second. What is the wavelength of an X-ray with a frequency of
1 answer:
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Answer:
Explanation:
The volume flow rate of a fluid in a pipe is given by:
where
A is the cross-sectional area of the pipe
v is the speed of the fluid
In this problem, at the initial point we have
v = 0.84 m/s is the speed of the water
r = 0.21 m is the radius of the pipe, so the cross-sectional area is
So, the volume flow rate is