I have all the answers here so take this
Answer:
Their velocity is 0m/s because the first box was only 10 kg and the second box was double the weight
Explanation:
Given that,
Potential = 75 kV
Exposure = 200 mR
Time = 0.2 sec
We need to calculate the x-ray fluence during this chest x-ray exam
Using formula of fluence

Put the value into the formula


We need to calculate the energy fluence
Using formula of energy fluence


We need to calculate dose -equivalent delivered to the bone, muscle, and fat
Using formula of dose

Where, D = dose
E = energy
t = time
Put the value into the formula


Hence, This is the required solution.
Answer:
The magnetic field is 
Explanation:
From the question we are told that
The mass of the metal is 
The current is 
The distance between the rail(length of the rod ) is 
The coefficient of kinetic friction is 
Generally the magnetic force is mathematically represented as

Given that the rod is moving at a constant velocity, it
=> 
Where
is the kinetic frictional force which is mathematically represented as

So

=> 
substituting values
=> 
=> 