Question

С какой скоростью двигался поезд массой 150т, если под действием силы сопротивления он прошел с момента начала торможения до остановки путь 50м? подробное решение пожалуйста

Answer 1

Дано: m=1500т=1,5*10^6 кг, F=150кН=1,5*10^5 Н, S=500м.Найти: v-?Решение:Так как грузовик вначале обладал некоторой скоростью, он имел и кинетическую энергию. Затем он полностью остановился, это значит, что вся кинетическая энергия перешла в работу торможения.Eк = Am*v^2/2 = F*Sv^2 = 2F*S / mv = 10 м/с

Answer 2

Calculation of the Speed of the Train

To calculate the speed of the train, we need to use the formula for acceleration:

Acceleration (a) = Change in velocity (Δv) / Time taken (t)

In this case, the train is decelerating, so the acceleration will be negative. The change in velocity is the final velocity (0 m/s) minus the initial velocity (v), and the time taken is the time it takes for the train to come to a stop.

Given: - Mass of the train (m) = 150 tons = 150,000 kg - Distance traveled (s) = 50 m - Final velocity (v_f) = 0 m/s

We can rearrange the formula to solve for the initial velocity (v):

v = v_f - a * t

To find the acceleration (a), we can use the formula:

Force (F) = Mass (m) * Acceleration (a)

The force acting on the train is the force of resistance, which can be calculated using the formula:

Force of Resistance (F_r) = Coefficient of Resistance (k) * Normal Force (N)

The normal force is equal to the weight of the train, which can be calculated using the formula:

Weight (W) = Mass (m) * Gravitational Acceleration (g)

Given: - Coefficient of Resistance (k) = Unknown - Gravitational Acceleration (g) = 9.8 m/s^2

We can substitute the formulas to find the acceleration:

F_r = k * W = k * m * g

a = F_r / m = (k * m * g) / m = k * g

Now we can substitute the value of acceleration into the equation for initial velocity:

v = v_f - a * t = 0 - (k * g) * t

Unfortunately, the coefficient of resistance (k) is not provided in the question, so we cannot calculate the exact speed of the train without this information. The coefficient of resistance depends on various factors such as the shape of the train, the surface it is moving on, and the air resistance.