Answer:

Explanation:
We are given that three resistors R1, R2 and R3 are connected in series.
Let
Potential difference across 
Potential difference across 
Potential difference across 
We know that in series combination
Potential difference ,
Using the formula

Hence, this is required expression for potential difference.
Answer:
Explanation:
The coordinate sketch for the system is shown in the attached file below. Also, in the cartesian coordinate system, since the height is less than the length and width, we did neglect the height. Thus, we eliminate the height and converted it to a two-dimension.
It is dependent upon the object's mass. The greater the mass of the object greater will be the inertia of the object, and hence it's resistance to change in motion as well.
For this case we must do a conversion. By definition we have to:
1 inch equals 2.54 centimeters
1 day equals 24 hours.
So, we have:
Canceling units we have:


Answer:

Torque = r x F
|F| = mg = 60 * 10 N = 600 N ( assuming g ~ 10m/s^2)
distance of fulcrum = torque / Force = 90/600 m = .15 m.