Question

Тело массой 2 кг движется с постоянной скоростью 20 м/с. На это тело в течение 4 с действовала постоянная сила 10 Н, направленная в сторону, противоположную его движению. Чему стала равна скорость тела в конце этого промежутка времени? Какой путь оно прошло за это время?

Answer 1

Изменение импульса тела mv-mv0=-Ft. Отсюда скорость конечная v=(-Ft+mv0)/m=(-10*4+2*20)/2=0. Знак минус из-за того, что сила в обратную сторону от движения направлена.
Ускорение m=F/m=10/2=5м/сс
Путь s=vot-att/2=20*4-5*16/2=80-40=40 м.

Answer 2

Problem Statement

A body with a mass of 2 kg is moving at a constant velocity of 20 m/s. A constant force of 10 N, directed opposite to the body's motion, acts on it for a duration of 4 seconds. We need to determine the final velocity of the body at the end of this time interval and the distance it has traveled during this time.

Solution

To solve this problem, we can use the equations of motion. The first equation relates velocity, time, and acceleration:

v = u + at,

where: - v is the final velocity, - u is the initial velocity (which is equal to the given constant velocity of 20 m/s), - a is the acceleration, and - t is the time interval (which is given as 4 seconds).

Since the body is moving at a constant velocity, the acceleration is zero. Therefore, the equation simplifies to:

v = u.

Thus, the final velocity of the body at the end of the 4-second interval is 20 m/s.

Next, we can use the equation that relates distance, velocity, and time:

s = vt,

where: - s is the distance traveled, - v is the velocity, and - t is the time interval.

Substituting the given values, we have:

s = (20 m/s) * (4 s) = 80 m.

Therefore, the body has traveled a distance of 80 meters during this time interval.

Conclusion

In conclusion, the final velocity of the body at the end of the 4-second interval is 20 m/s, and the distance it has traveled during this time is 80 meters.