Question

У скільки разів швидкість легкового автомобіля,що дорівнює 72 кям/год, більша від швидкості вітру 4 м/с ? Потяг і автомобіль рухаються в одному напрямі. Чи може автомобіль обігнати потяг, якщо швидкість автомобіля - 29 м/с, а потяга - 108 км/год?варіанти відповідейтакніВелосипедист за 0,5 год проїхав 10 км.Яа середня швидкість рху велосипедиста?варіанти відповідей2 км/год20 км/год20 м/с2 м/сЯкий шлях проїхав автомобіль за 1,5 хв, якщо його швидкість 20 м/с?За який час човен , який пливе за течією річки , подолає відстань 13,5 км, якщо швидкість течії 5 м/с?Тіло рухалося 15 с зі швидкістю 8 м/с і 3 с - зі швидкістю 20 м/с.Яка його середня швидкість?​

Answer 1

Ответ:

1) 72 км/ч = 72/3.6 = 20 м/с

20/4 = 5 м/с

2) 29 м/с = 29*3.6 = 104.4 км/ч

104.4 < 108 км/ч

ответ нет

3) v = 10/0.5 = 20 км/ч

4) S = t*v = 90 * 20 = 1800 м

5)

v = 5 * 3.6 = 18 км/ч

t = S/v = 13.5 / 18 = 0.75 ч

6)

v ср = всё расстояние / всё время

S = 15*8 + 3*20 = 180 м

t = 15 + 3 = 18 c

v = S/t = 180 / 18 = 10 м/с

Answer 2

Calculation of Car Speed Relative to Wind Speed

To determine how many times faster the speed of a car traveling at 72 km/h is compared to a wind speed of 4 m/s, we need to convert the units to a common measurement.

1 kilometer per hour (km/h) is equal to 0.2778 meters per second (m/s).

Therefore, the car's speed of 72 km/h is equal to 20 m/s.

To find out how many times faster the car is compared to the wind speed, we divide the car's speed by the wind speed:

Car speed / Wind speed = 20 m/s / 4 m/s = 5 times faster.

So, the car is five times faster than the wind speed of 4 m/s.

Overtaking the Train

To determine if the car can overtake the train, we need to compare their speeds.

The car's speed is given as 29 m/s, and the train's speed is given as 108 km/h.

To compare the speeds, we need to convert the units to a common measurement.

1 kilometer per hour (km/h) is equal to 0.2778 meters per second (m/s).

Therefore, the train's speed of 108 km/h is equal to 30 m/s.

Since the car's speed is less than the train's speed, the car cannot overtake the train.

Average Speed of a Cyclist

To calculate the average speed of a cyclist, we need to know the distance traveled and the time taken.

In this case, the cyclist traveled a distance of 10 km in 0.5 hours.

To calculate the average speed, we divide the distance by the time:

Average speed = Distance / Time = 10 km / 0.5 hours = 20 km/h.

Therefore, the cyclist's average speed is 20 km/h.

Distance Traveled by a Car

To calculate the distance traveled by a car in 1.5 minutes (or 1.5/60 hours) at a speed of 20 m/s, we use the formula:

Distance = Speed × Time.

Substituting the given values:

Distance = 20 m/s × 1.5/60 hours = 0.5 km.

Therefore, the car traveled a distance of 0.5 km.

Time to Cover a Distance with River Current

To calculate the time it takes for a boat to cover a distance of 13.5 km with a river current speed of 5 m/s, we need to consider the relative velocities.

The boat's speed relative to the river is the difference between the boat's speed and the river current speed. In this case, the boat's speed is not provided, so we cannot determine the exact time.

Average Speed Calculation

To calculate the average speed of an object that moves at different speeds for different durations, we need to know the total distance traveled and the total time taken.

In this case, the object moved at a speed of 8 m/s for 15 seconds and at a speed of 20 m/s for 3 seconds.

To calculate the average speed, we divide the total distance by the total time:

Average speed = Total distance / Total time.

The total distance can be calculated by adding the distances traveled at each speed:

Total distance = Distance at 8 m/s + Distance at 20 m/s.

The distance traveled at each speed can be calculated using the formula:

Distance = Speed × Time.

Substituting the given values:

Distance at 8 m/s = 8 m/s × 15 s = 120 m.

Distance at 20 m/s = 20 m/s × 3 s = 60 m.

Therefore, the total distance is:

Total distance = 120 m + 60 m = 180 m.

The total time is the sum of the durations at each speed:

Total time = Time at 8 m/s + Time at 20 m/s.

Substituting the given values:

Total time = 15 s + 3 s = 18 s.

Finally, we can calculate the average speed:

Average speed = Total distance / Total time = 180 m / 18 s = 10 m/s.

Therefore, the average speed of the object is 10 m/s.