1. There are three 15.0 Ω resistors connected in series across a 90 V battery.
a) What is the total (equivalent) resistance of the circuit (answer in ohms)? *
b) what is the current in the circuit (answer in amps)? *
c) What is the voltage drop across one of the resistors (answer in Volts)? *
d) What is the current anywhere in the circuit?

a)

b) 2 A

c) 30 V

d) 2 A

Explanation:

a)

Resistors are said to be connected in series when they are connected along the same branch of the circuit: therefore, the current flowing through them is the same (while they can have different potential difference across each of them).

For a series of N resistors, the equivalent resistance is given by the sum of the individual resistances:

In this problem, we have three resistors, having resistances of:

Therefore, the equivalent resistance of the three resistors in series is:

b)

The relationship between voltage frop, current and resistance in a circuit is given by Ohm's Law:

where

V is the potential difference

R is the resistance

I is the current

For this circuit, we have:

V = 90 V is the potential difference across the three resistors in series

is the equivalent resistance of the circuit

Therefore, the current through the circuit is:

c)

In a series circuit, the current through the resistors is the same, however the voltage frop across each resistor can be different (if they have differnet resistances).

In this case, all the three resistors have same resistance, so the voltage drop across each of them is given again by Ohm's Law:

where, in this case

R is the individual resistance

I is the current through the resistor

Here we have:

is the resistance of each resistor

I = 2 A is the current

So, the voltage drop across each resistor is

d)

As we said in part b, the current is the same in every part of a circuit in series, since the three resistors are connected in series: so here, the current is 2 A in every point of the circuit.

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

                                              ⇒      

here   k is the proportionality constant whose value is 1.

                                                            [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.