Question

Троллейбус массой 11т движется равномерно прямолинейно со скоростью 10м/с. Сила тока в обмотке электродвигателя равна 40А, напряжение равно 550В. Чему равен коэффициент трения? (Потерями энергии в электродвигателе пренебречь.)

Answer 1

F*V=I*U

F=u*m*g u*m*g*V=I*U

u=I*U/m*g*V=40*550/11*10^3*10*10=0.02

Answer 2

Calculation of the Friction Coefficient

To calculate the friction coefficient, we need to use the given information about the mass of the trolleybus, its speed, and the current and voltage in the motor winding. However, the search results did not provide any relevant information to directly calculate the friction coefficient. Therefore, we will need to use other methods to find the answer.

The friction coefficient can be determined by analyzing the forces acting on the trolleybus. In this case, we can consider the driving force provided by the electric motor and the opposing force due to friction.

The driving force provided by the electric motor can be calculated using the formula:

Driving Force = Current x Magnetic Field Strength

The magnetic field strength can be calculated using the formula:

Magnetic Field Strength = (Voltage / Number of Turns) x Magnetic Flux Density

To calculate the opposing force due to friction, we can use the formula:

Opposing Force = Friction Coefficient x Normal Force

The normal force can be calculated using the formula:

Normal Force = Mass x Gravity

Since the trolleybus is moving at a constant speed, the driving force provided by the electric motor is equal to the opposing force due to friction. Therefore, we can set up the following equation:

Driving Force = Opposing Force

Let's calculate the friction coefficient using the given information:

Given: - Mass of the trolleybus = 11 t (tonnes) = 11000 kg - Speed of the trolleybus = 10 m/s - Current in the motor winding = 40 A - Voltage = 550 V

First, let's calculate the magnetic field strength:

Magnetic Field Strength = (Voltage / Number of Turns) x Magnetic Flux Density

Since we don't have information about the number of turns and the magnetic flux density, we cannot calculate the magnetic field strength.

Therefore, without the necessary information, it is not possible to calculate the friction coefficient in this case.