Question

Лодке необходимл проплыть 240м туда и обратно один раз по реке, а другой раз по озеру. Cкорость течения реки 1 м/c, а скорость лодки относительо воды 5м/c. На сколько больше времени займет движение лодки по реке,чем по озеру?

Answer 1

Vпотеч. = Vтеч. +V ; Vпртеч. = V - Vтеч.

Vпотеч. = 5+1 = 6 ; Vпртеч. = 5-1 = 4

t1 = S/Vпотеч. + S/Vпртеч. = 240/6 + 240/4 = 100c. - по реке туда-обратно.

t2 = S/V = 480/5 = 96 c

t = t1-t1 = 100-96 = 4секунды.

 

Answer 2

Calculation of Time Difference

To calculate the time difference between the boat's movement on the river and the lake, we need to consider the speed of the current and the speed of the boat relative to the water.

Let's denote the distance as d (240m) and the speed of the current as v_c (1 m/s). The speed of the boat relative to the water is given as v_b (5 m/s).

The time taken to travel a certain distance can be calculated using the formula:

Time = Distance / Speed

1. Time taken to travel on the river: - The boat's speed relative to the water is v_b (5 m/s). - The effective speed of the boat when moving against the current is v_b - v_c (5 m/s - 1 m/s = 4 m/s). - Therefore, the time taken to travel 240m on the river is 240m / (v_b - v_c).

2. Time taken to travel on the lake: - The boat's speed relative to the water is v_b (5 m/s). - Since there is no current on the lake, the boat's effective speed remains the same. - Therefore, the time taken to travel 240m on the lake is 240m / v_b.

To find the time difference, we subtract the time taken on the lake from the time taken on the river:

Time difference = (240m / (v_b - v_c)) - (240m / v_b)

Let's calculate the time difference.