Question

Поезд московского метрополитена отходит от станции со средним ускорением 1м/с2.Через сколько времени он достигнет предельной ск 75км/ч?

Answer 1

При переводе 
75км/ч~21м/с
следовательно поезд достигнет данной скорости за 21 секунду

Answer 2

Calculation of Time to Reach Maximum Speed

To calculate the time it takes for a train in the Moscow Metro to reach its maximum speed, we can use the formula:

v = u + at

Where: - v is the final velocity (maximum speed) of the train, - u is the initial velocity of the train (which is assumed to be 0 in this case), - a is the acceleration of the train, and - t is the time taken to reach the final velocity.

In this case, the train has a constant acceleration of 1 m/s^2 and the maximum speed is 75 km/h (or 20.83 m/s). Let's calculate the time it takes for the train to reach this speed.

Step 1: Convert the maximum speed from km/h to m/s: - 75 km/h = 75,000 m/3600 s = 20.83 m/s

Step 2: Substitute the values into the formula: - v = 20.83 m/s - u = 0 m/s - a = 1 m/s^2

Step 3: Solve for t: - 20.83 = 0 + 1t - t = 20.83 s

Therefore, it takes approximately 20.83 seconds for the train to reach its maximum speed of 75 km/h.