Answer: B
Explanation:
It's not the time it took to heat the substance, so that rules out A and C.
This means that we only have to choose between
B. the area of contact
D. the area of the substances
(since everything else in each of those answers are the same)
Area of contact matters more (e.g. an object with greater surface area is exposed to the air more, will lose/gain heat quicker than an object with less surface area).
To solve this problem we will apply the concept related to the magnetic dipole moment that is defined as the product between the current and the object area. In our case we have the radius so we will get the area, which would be



Once the area is obtained, it is possible to calculate the magnetic dipole moment considering the previously given definition:



Therefore the magnetic dipole moment is 
Answer:
If you are simply looking for the X component then the most applicable formula from the choices given is Tx + Ux+ Vx. This means that you will add all x-components. For example: If a man walking along the x-axis walks 10 meters to the right, 5 back and 2 meters forward, what is the resultant vector?
Answer:
FC vector representation

Magnitude of FC

Vector direction FC
degrees: angle that forms FC with the horizontal
Explanation:
Conceptual analysis
Because the particle C is close to two other electrically charged particles, it will experience two electrical forces and the solution of the problem is of a vector nature.
The directions of the individual forces exerted by qA and qB on qC are shown in the attached figure; The force (FAC) of qA over qC is repulsive because they have equal signs and the force (FBC) of qB over qC is attractive because they have opposite signs.
The FAC force is up in the positive direction and the FBC force forms an α angle with respect to the x axis.
degrees
To calculate the magnitudes of the forces we apply Coulomb's law:
Equation (1): Magnitude of the electric force of the charge qA over the charge qC
Equation (2)
: Magnitude of the electric force of the charge qB over the charge qC
Known data





Problem development
In the equations (1) and (2) to calculate FAC Y FBC:


Components of the FBC force at x and y:


Components of the resulting force acting on qC:


FC vector representation

Magnitude of FC

Vector direction FC
degrees: angle that forms FC with the horizontal