Question

При взаимодействии на тело массой 500 кг сила 20 Н в течении времени t его скорость изменяется от 5 м/с до 54 км/ч. Вычислите время действия силы.

Answer 1

2- ой закон Ньютона в импульсной форме: Ft=mV-mVo  откуда  
t=(mV-mVo)/F=m*(V-Vo)/F=500*(15-5)/20=250 [c]
V=54 км/ч=15 м/с

Answer 2

Calculation of Time of Action

To calculate the time of action of a force, we can use the formula t = s/v, where t is the time, s is the distance traveled, and v is the velocity.

Given: - Mass of the body (m) = 500 kg - Force (F) = 20 N - Initial velocity (u) = 5 m/s - Final velocity (v) = 54 km/h

First, let's convert the final velocity from km/h to m/s: - 54 km/h = 54 * (1000/3600) m/s = 15 m/s Next, we need to find the distance traveled (s). We can use the formula v = u + at, where a is the acceleration and t is the time. Since the force is constant, we can use Newton's second law of motion F = ma to find the acceleration: - F = ma - 20 N = 500 kg * a - a = 20 N / 500 kg = 0.04 m/s^2

Using the formula v = u + at, we can find the time (t) it takes for the velocity to change from 5 m/s to 15 m/s: - 15 m/s = 5 m/s + 0.04 m/s^2 * t - 10 m/s = 0.04 m/s^2 * t - t = 10 m/s / 0.04 m/s^2 = 250 s

Therefore, the time of action of the force is 250 seconds.

Please note that the calculation assumes a constant force and neglects other factors such as friction and air resistance.

Conclusion

The time of action of a force of 20 N on a body with a mass of 500 kg, where the velocity changes from 5 m/s to 54 km/h, is calculated to be 250 seconds.

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