I believe it is D. Earth spinning on it's axis.
Answer:

Explanation:
Electric field in a given region is given by equation

as we know the relation between electric field and potential difference is given as

so here we have


here we know that
and 
so we will have

so we will have

Answer:
20 N exerts no torque about the pivot.
14 N exerts a counterclockwise torque of 14 * .3 = .42 N-m
6 exerts a clockwise torque of 6 * .7 = .42 N-m
The meter stick will not turn because there is no net torque on the meter stick.
The objects that look black are all tied for first place.
Answer:
(a). The rotational inertia is 
(b). The magnitude of the magnetic torque is 
Explanation:
Given that,
Mass of neutron 
Density of neutron 
(a). We need to calculate the rotational inertia
Using formula of rotational inertia for sphere
...(I)
We know that,

Put the value of volume


Put the value of R in equation (I)

Put the value into the formula


The rotational inertia is
.
(b). We need to calculate the magnitude of the magnetic torque
Using formula of torque

Put the value into the formula


The magnitude of the magnetic torque is 
Hence, (a). The rotational inertia is 
(b). The magnitude of the magnetic torque is 