Answer:
The third particle should be at 0.0743 m from the origin on the negative x-axis.
Explanation:
Let's assume that the third charge is on the negative x-axis. So we have:

We know that the electric field is:

Where:
- k is the Coulomb constant
- q is the charge
- r is the distance from the charge to the point
So, we have:

Let's solve it for r(3).
Therefore, the third particle should be at 0.0743 m from the origin on the negative x-axis.
I hope it helps you!
Frictional force and Applied force has same “magnitude” and “opposite” direction.
Option: B
<u>Explanation</u>:
When a book is moved horizontally by applying “force” on the book, the frictional force is opposed to the book by the table. Here, this “frictional force” is opposing the book has the same force what we applied on the book but this frictional force and the applied force are opposite in direction. Always the “frictional force” is opposite to the “applied force” which stops the object to move. For example, if a force applied leftward to the object the frictional force is acted on the right side of the object.
When two objects are in contact they experience a "frictional force". This "frictional force" acts opposite to the force applied on to move the object.
Formula for "frictional force" is 
Where,
is coefficient of friction and N is normal force.
if it moves 7m/s, that means every second it goes 7m. Now we just multiply by the time (20 seconds) and end up with 140m.
Answer:
4V
Explanation:
First, we calculate the total resistance to the given battery cell of emf 5V. The total resistance is the sum of all the resistance in the cell i.e.
Total resistance = 2Ω + 8Ω = 10Ω
Using ohms law equation to calculate the current passing through the battery cell:
V = IR
Where; V = voltage, I = current, R = resistance
5V = I × 10Ω
I = 5/10
I = 0.5A
Terminal voltage is calculated by the us of the following equation:
V=emf−IR
Where; R is internal resistance
V = 5 - (0.5 × 2)
V = 5 - 1
V = 4V
Therefore, the potential difference across the terminals of the battery cell is 4V