Question

ДАМ 99 БАЛЛОВ! Аккумуляторная батарея на автомобиле имеет ЭДС=12,6 В и внутреннее сопротивление r=0,06 Ом.При пуске двигателя по стартеру течет ток I=80 А в течение t=3 с.Какое напряжение при этом на стартере, чему равна работа сторонних сил в аккумуляторе, какую работу совершает стартер? Подробно,пожалуйста!

Answer 1

Из ф-лы  I=Е-U/R+r  получаем 80а=12.6-U/R+0.06
неизвестные остаются напряжениеU,на внешней цепи и R- сопротивление обмотки стартёра.
Если принять U=7в, это напряжение на стартёре,  а R=0.01ом ,то подставив значения всё сходится.
Работа сторонних сил в аккумуляторе: А=U*I*t=7в*80а*3с=1680Дж
Работа стартёра : А=U*I*t=7в*80а*3с=1680Дж

Answer 2

Calculation of Voltage Drop and Work Done

To calculate the voltage drop and work done in the given scenario, we can use Ohm's Law and the formula for work done.

Ohm's Law states that the voltage drop across a resistor is equal to the current flowing through it multiplied by its resistance:

V = I * R

Where: - V is the voltage drop (in volts) - I is the current flowing through the resistor (in amperes) - R is the resistance of the resistor (in ohms)

In this case, the resistor is the internal resistance of the battery, which is given as r = 0.06 Ω.

The current flowing through the resistor is I = 80 A and the time for which the current flows is t = 3 s.

Using Ohm's Law, we can calculate the voltage drop across the internal resistance of the battery:

V = I * r

Substituting the given values:

V = 80 A * 0.06 Ω = 4.8 V

Therefore, the voltage drop across the internal resistance of the battery during the engine start is 4.8 V.

The work done by an external force on an object can be calculated using the formula:

Work = Force * Distance

In this case, the external force is the current flowing through the starter, and the distance is the voltage drop across the starter.

The work done by the starter can be calculated as:

Work = I * V

Substituting the given values:

Work = 80 A * 4.8 V = 384 J

Therefore, the work done by the starter during the engine start is 384 Joules.

Voltage and Work Calculation Summary:

- The voltage drop across the starter is 4.8 V. - The work done by the starter during the engine start is 384 Joules.

Please note that the calculations provided are based on the given values and assumptions.