Question

По кругу радиуса 2 км в одном направлении движутся пешеход и велосипедист, стартовав одновременно из одной точки. Скорость пешехода равна 5км/ч , а велосипедиста — 15 км\ч. На сколько полных кругов велосипедист обгонит пешехода через 5 часов после старта?

Answer 1

1.15*5=75(км)-проедет велосипедист за 5 часов
2.5*5=25 км- пройдёт пешеход
3.75-25=50(км)-разница в пути

С=2πR=2*3*2=12 (км) -длина окружности (π≈3)

4.50:12=4 (ост 2)

Ответ: 4 полных круга

Если π считать равным 3.14,то 50:12.56 ≈3.98

Ответ: 3 полных круга.

Answer 2

1) 5*5=25 (км) пройдёт пешеход за 5 часов

2) 15*5=75 (км) проедет велосипедист за 5 ч

3) С=2пr

  2*3,14*2=12,56 (км) длина одного круга (приблизительно, т.к. значение п взято приближённое)

4) 25:12,56 = 1,99... (кругов) пройдёт пешеход за 5 ч. круг

5) 75:12,56 = 5,97... (кругов) велосипедист проедет за 5 часов

6) 5,97-1,99= 3,98 , т.е. целых 3 круга

Ответ: на 3 круга

Answer 3

Problem Analysis

We are given that a pedestrian and a cyclist start simultaneously from the same point and move in the same direction around a circle with a radius of 2 km. The pedestrian's speed is 5 km/h, and the cyclist's speed is 15 km/h. We need to determine how many complete circles the cyclist will overtake the pedestrian after 5 hours.

Solution

To solve this problem, we need to calculate the distances covered by the pedestrian and the cyclist after 5 hours and then determine the number of complete circles the cyclist completes.

The distance covered by an object can be calculated using the formula: distance = speed × time.

Let's calculate the distances covered by the pedestrian and the cyclist after 5 hours:

- Distance covered by the pedestrian = 5 km/h × 5 h = 25 km. - Distance covered by the cyclist = 15 km/h × 5 h = 75 km.

Since the circumference of a circle is given by the formula: circumference = 2πr, where r is the radius of the circle, the distance covered by the cyclist is equal to the circumference of the circle multiplied by the number of complete circles.

Let's calculate the number of complete circles the cyclist completes:

- Circumference of the circle = 2π × 2 km = 4π km. - Number of complete circles = Distance covered by the cyclist / Circumference of the circle = 75 km / (4π km) ≈ 5.98.

Therefore, the cyclist will overtake the pedestrian approximately 5.98 complete circles after 5 hours.

Note: Since we cannot have a fraction of a complete circle, we can round down the number of complete circles to the nearest whole number. In this case, the cyclist will overtake the pedestrian after approximately 5 complete circles.

Answer

The cyclist will overtake the pedestrian through approximately 5 complete circles after 5 hours from the start.