Question

Поезд массой m=150т двигался со скоростью v=72км/ч. При торможении до полной остановки поезд прошёл путь S =500м. Определитель силу сопротивления движению

Answer 1

F=A/S
A= Ek2-Ek1=m(v²-v0²)/2=mv²/2(т.к. конечная скорость равна 0)
F=mv²/2S
F=150*10³*20²/2*500=60*10⁶/10³=60*10³Н=60кН

Answer 2

Calculation of the Resistance Force

To determine the resistance force acting on the train during braking, we can use the equation:

F = m * a

where: - F is the force (resistance force in this case) - m is the mass of the train - a is the acceleration

Given: - Mass of the train, m = 150 tons = 150,000 kg - Initial velocity, v = 72 km/h = 20 m/s - Final velocity, u = 0 m/s (since the train comes to a complete stop) - Distance traveled, S = 500 m

To calculate the acceleration, we can use the equation:

v^2 = u^2 + 2aS

Rearranging the equation to solve for acceleration, we get:

a = (v^2 - u^2) / (2S)

Substituting the given values, we have:

a = (20^2 - 0^2) / (2 * 500) = 400 / 1000 = 0.4 m/s^2

Now, we can calculate the resistance force using the equation F = m * a:

F = 150,000 kg * 0.4 m/s^2 = 60,000 N

Therefore, the force of resistance acting on the train during braking is 60,000 Newtons.