Question

В электрокаре используется аккумулятор с напряжением 80 В, максимальная потребляемая от аккумулятора мощность равна 25 кВт. Максимальная сила тяги электрокара 1250 Н, при этом обеспечивается скорость движения 14 м/с. За какое время разрядится аккумулятор при движении электрокара с максимальной скоростью, если емкость его аккумулятора составляет 360 А*час? Каков в процентах КПД электрокара? Время вводить с точностью до сотых, значение КПД - с точностью до целых.

Answer 1

КПД=F*v/P=1250*14/25000=0.7 (70%)

I=F*v/U=17500/80=218.75 A

t=360/218.75=1.64 ч

Answer 2

Calculation of Battery Discharge Time

To calculate the time it takes for the battery to discharge while the electric car is moving at its maximum speed, we need to determine the energy consumption per unit time.

The maximum power consumed by the battery is given as 25 kW (kilowatts). Since power is the rate at which energy is consumed, we can calculate the energy consumption per second using the formula:

Energy consumption per second = Power

Given that the maximum power consumed is 25 kW, the energy consumption per second is also 25 kW.

To find the time it takes for the battery to discharge, we need to divide the battery capacity by the energy consumption per second. The battery capacity is given as 360 A*h (ampere-hours). To convert this to watt-hours, we multiply it by the battery voltage of 80 V:

Battery capacity in watt-hours = Battery capacity in A*h * Battery voltage

Substituting the given values:

Battery capacity in watt-hours = 360 A*h * 80 V

Now, we can calculate the time it takes for the battery to discharge:

Discharge time = Battery capacity in watt-hours / Energy consumption per second

Let's calculate the values:

Battery capacity in watt-hours = 360 A*h * 80 V = 28,800 Wh

Discharge time = 28,800 Wh / 25 kW = 1,152 seconds

Therefore, the battery will discharge in approximately 1,152 seconds when the electric car is moving at its maximum speed.

Calculation of Electric Car Efficiency (КПД)

To calculate the efficiency of the electric car, we need to determine the ratio of useful output power to the input power.

The useful output power of the electric car is the maximum traction force multiplied by the maximum speed:

Useful output power = Maximum traction force * Maximum speed

Given that the maximum traction force is 1250 N (newtons) and the maximum speed is 14 m/s (meters per second), we can calculate the useful output power:

Useful output power = 1250 N * 14 m/s

The input power is the power consumed by the battery, which is given as 25 kW.

Now, we can calculate the efficiency of the electric car:

Efficiency (КПД) = (Useful output power / Input power) * 100

Let's calculate the values:

Useful output power = 1250 N * 14 m/s = 17,500 W

Efficiency (КПД) = (17,500 W / 25 kW) * 100 = 70%

Therefore, the efficiency of the electric car is approximately 70%.

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