Question

Человек прыгает с подножки поезда идущего со скоростью 18 км/ч. В момент прыжка он отталкивается назад и приобретает относительно поезда скорость 2 м/с. На каком расстоянии приземлится человек от того места где он прыгнул если высота подножки над землей 1,25 м?

Answer 1

скорость поезда =5м/c

скорость человека относительно поезда = 2м/c

=> относительно земли он прыгнул со скоростью 5-2=3м/c

найдем время падения 

H=gt^2/2

t^2=2H/g

t=0.5с

теперь можно найти расстояние

S=ut

S=3*0.5=1.5м

ответ 1.5 метра

Answer 2

Calculation of the Distance the Person Will Land

To calculate the distance at which the person will land from the point where they jumped, we need to consider the relative velocities of the person and the train.

Given: - Speed of the train: 18 km/h - Speed of the person relative to the train: 2 m/s - Height of the footboard above the ground: 1.25 m

To solve this problem, we can use the equation of motion:

s = ut + (1/2)at^2

Where: - s is the distance traveled - u is the initial velocity - t is the time - a is the acceleration

In this case, the initial velocity (u) is 2 m/s, the acceleration (a) is 0 (since the person is not accelerating or decelerating), and we need to find the time (t) and distance (s).

To find the time, we can use the equation:

v = u + at

Where: - v is the final velocity

In this case, the final velocity (v) is 0 (since the person will come to a stop when they land). Rearranging the equation, we get:

t = -u / a

Substituting the values, we have:

t = -2 m/s / 0 m/s^2

Since the acceleration is 0, the time taken (t) is undefined. This means that the person will not come to a stop relative to the train and will continue to move with the same velocity.

Therefore, the person will land at the same distance from the point where they jumped, which is the height of the footboard above the ground: 1.25 m.

Please note that this calculation assumes ideal conditions and neglects factors such as air resistance and the curvature of the Earth.