Question

2задача:На полу лифта находится тело массой 50 кг.Лифт поднимается так,что за 3 с его скорость изменилась от 8 до 2 м/с.Найдите силу давления тела на пол лифта.Ответ должен получиться 400Н (Ньютонов),но у меня не получается...

Answer 1

a  = (V1 - V0) / t = (2 - 8) / 3 = -2 м/с²

F = m * (g + a) = 50 * (10 - 2) = 400 H.

Answer 2

Problem Analysis

We are given the following information: - Mass of the body: 50 kg - Change in velocity of the lift: from 8 m/s to 2 m/s in 3 seconds

We need to find the force of pressure exerted by the body on the floor of the lift.

Solution

To find the force of pressure, we can use Newton's second law of motion, which states that the force acting on an object is equal to the product of its mass and acceleration.

In this case, the acceleration can be calculated using the change in velocity and the time taken. The initial velocity is 8 m/s, the final velocity is 2 m/s, and the time taken is 3 seconds.

Let's calculate the acceleration first: Acceleration (a) = (Change in velocity) / (Time taken) Acceleration (a) = (2 m/s - 8 m/s) / 3 s Acceleration (a) = -6 m/s / 3 s Acceleration (a) = -2 m/s^2

Now, we can calculate the force of pressure using Newton's second law: Force (F) = Mass (m) * Acceleration (a) Force (F) = 50 kg * -2 m/s^2 Force (F) = -100 N

The negative sign indicates that the force is directed downwards, towards the floor of the lift. However, the force of pressure is always positive, so we take the magnitude of the force.

Therefore, the force of pressure exerted by the body on the floor of the lift is 100 N.

Conclusion

The force of pressure exerted by the body on the floor of the lift is 100 N.