Explanation:
It is given that,
Force applied to object, 
Position,
(b) The cross product of force and position vector is used to find the net torque about the z axis. It is given by :



or

The torque is acting in -z axis.
(a) The magnitude of torque is given by :


Hence, this is the required solution.
Ok so the first thing you need to do is im not gonna help you
Explanation:
it is given that, the linear charge density of a charge, 
Firstly, we can define the electric field for a small element and then integrate for the whole. The very small electric field is given by :
..........(1)
The linear charge density is given by :


Integrating equation (1) from x = x₀ to x = infinity



Hence, this is the required solution.
For simplicity, let's call vector B-A vector C Then C is
Cx = (-6.1 - 2.2)
Cy = (-2.2 - (-6.9)) Or,
Cx = -8.3 Cy = 4.7
The magnitude is found with the Pythagorean theorem
||C|| = √(-8.3² + 4.7²) = 9.538
Solid to liquid
Liquid to solid
By adding or removing heat energy aka thermal energy