Question

Расстояние между двумя станциями поезд прошел со средней скоростью 72км/ч за 20мин .Разгоны торможения вместе длились 4мин а остальное время он двигался равномерно .Найти скорость поежда на равномерном движении

Answer 1

Путь пройденный поездом состоит из 3 участков: разгон в течение 2 мин, равномерное движение с Vmax в течение 20-4=16 мин, торможение в течение 2 мин. Значит можно записать:S=Vmax/2*2+ Vmax*16+ Vmax/2*2= Vmax*18Тогда Vср=S/t= Vmax*18/20Vmax= Vср*20/18=72*20/18=80 км/ч

Answer 2

Calculation of Train Speed during Uniform Motion

To find the speed of the train during uniform motion, we need to calculate the total distance covered by the train and the time taken for that portion of the journey.

Given information: - Average speed of the train: 72 km/h - Time taken for uniform motion: 20 minutes - Time taken for acceleration and deceleration: 4 minutes

Let's calculate the distance covered during uniform motion first.

Step 1: Convert the time taken for uniform motion from minutes to hours. - 20 minutes = 20/60 hours = 1/3 hours

Step 2: Calculate the distance covered during uniform motion using the formula: - Distance = Speed × Time

Substituting the values: - Distance = 72 km/h × 1/3 hours

Simplifying the expression: - Distance = 24 km

Therefore, the distance covered during uniform motion is 24 km.

Now, let's calculate the speed of the train during uniform motion.

Step 3: Calculate the speed using the formula: - Speed = Distance / Time

Substituting the values: - Speed = 24 km / (1/3 hours)

Simplifying the expression: - Speed = 72 km/h

Therefore, the speed of the train during uniform motion is 72 km/h.