A prototype electric car is powered by a 400 V battery pack. What is the resistance of the motor circuit when 2.8 x 105 C passes through the circuit in 1.00 h?

Resistance = 5.14 Ohms

Explanation:

Given the following data;

Quantity of charge, Q = 2.8*10^5C

Time = 1hour to seconds = 60*60 = 3600 seconds

Voltage = 400V

First of all, we would find the current flowing through

Q = it

2.8*10^5 = I*3600

Current, I = 280000/3600

Current, I = 77.78 Amps

To find the resistance;

Ohm's law states that at constant temperature, the current flowing in an electrical circuit is directly proportional to the voltage applied across the two points and inversely proportional to the resistance in the electrical circuit.

Mathematically, Ohm's law is given by the formula;

Voltage = current * resistance

Resistance = voltage/current

Resistance = 400/77.78

Resistance = 5.14 Ohms

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s