Explanation:
It is given that,
Mass of lithium, 
It is accelerated through a potential difference, V = 224 V
Uniform magnetic field, B = 0.724 T
Applying the conservation of energy as :


q is the charge on an electron

v = 78608.58 m/s

To find the radius of the ion's path in the magnetic field. The centripetal force is balanced by the magnetic force as :



r = 0.0078 meters
So, the radius of the path of the ion is 0.0078 meters. Hence, this is the required solution.
Answer:
the answer to your question is C, Amount of mass in a given volume
Explanation:
net force= the sum of all the forces acting on the object
the frictional force is opposite to the direction of motion of the object
If the object moves to the right (positive) then the friction force moves to the left (negative).
so the net force: 50 N - 5 N = 45 N (B)
Answer:
to prevent the derailing of the train due to thermal expansion.