Answer:
Part a)

Part b)

Explanation:
Part a)
Torque on the rod is due to two forces
(i) Due to weight of the rod at mid point
(ii) Due to external force applied at the end
Now we have



Part b)
As per Newton's law we know that

now we have


Answer:
It's actually 100V
Explanation:
To answer this, you'd need to use Ohm's law, which states that Voltage is equivalent to the product of Current and Resistance (V=IR).
V = 50 × 2
V = 100
Therefore the voltage is a 100V.
None of the answers you have listed match this though, so I'm guessing it either must be typo or the question itself is wrong.
To look for the acceleration, it will come from:
vf^2=v0^2+2ad
where:
vf = final velocity = 0
v0 = initial velocity =251 m/s
a = acceleration
d= distance traveled = 0.237 m
0=251^2+2a(0.237 )
a= -251 ^2 / (2*0.237) =-132 913.502 m/s/s
we find the force from:
F = ma = 0.0115kg*(-1.32x10^5m/s/s) = -1518 N
the negative sign shows that the force is in the direction contradictory the
bullet's motion
The interaction between two like-charged objects is repulsive. ... Positively charged objects and neutral objects attract each other; and negatively charged objects and neutral objects attract each other.