Question

50 баллов!! Тело массой 2 кг, едет вперед равномерно со скоростью 9 км/ч, определить мощность силы тяги и совершаемую работу, если коэффициент трения 0,06. За 10 с.

Answer 1

Ответ:

Объяснение:

Дано:

m = 2 кг

V = 9 км/ч = 2,5 м/с

μ = 0,06

t = 10 c

_________

N - ?

A - ?

1)

Сила трения:

Fтр = μ·m·g = 0,06·2·10 = 1,2 Н

2)

Поскольку тело движется равномерно, то сила тяги равна силе трения:

Fт = Fтр = 1,2 Н

Тогда мощность:

N = Fтр·V = 1,2·2,5 = 3 Вт

3)

Совершенная работа:

A = N·t = 3·10 = 30 Дж

Answer 2

Problem Analysis

We are given the following information: - Mass of the body: 2 kg - Velocity of the body: 9 km/h - Coefficient of friction: 0.06 - Time: 10 s

We need to determine the power of the driving force and the work done.

Calculating Power

Power is defined as the rate at which work is done or energy is transferred. It can be calculated using the formula:

Power = Work / Time

To calculate the power, we need to calculate the work done first.

Calculating Work Done

The work done is given by the formula:

Work = Force x Distance

In this case, the force is the driving force, and the distance is the displacement of the body.

Calculating Driving Force

The driving force can be calculated using Newton's second law of motion:

Force = Mass x Acceleration

To calculate the acceleration, we need to consider the forces acting on the body. In this case, the only force is the driving force, which is opposed by the force of friction.

Calculating Frictional Force

The frictional force can be calculated using the formula:

Frictional Force = Coefficient of Friction x Normal Force

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

Weight = Mass x Gravity

Calculating Work Done

The work done can be calculated using the formula:

Work = Force x Distance

In this case, the distance is equal to the displacement of the body, which can be calculated using the formula:

Displacement = Velocity x Time

Now, let's calculate the power and work done.

Calculation

Given: - Mass of the body (m) = 2 kg - Velocity of the body (v) = 9 km/h = 2.5 m/s - Coefficient of friction (μ) = 0.06 - Time (t) = 10 s - Acceleration due to gravity (g) = 9.8 m/s^2

1. Calculate the driving force: - Weight = Mass x Gravity - Weight = 2 kg x 9.8 m/s^2 - Weight = 19.6 N - Frictional Force = Coefficient of Friction x Normal Force - Frictional Force = 0.06 x 19.6 N - Frictional Force = 1.176 N - Driving Force = Frictional Force - Driving Force = 1.176 N

2. Calculate the work done: - Displacement = Velocity x Time - Displacement = 2.5 m/s x 10 s - Displacement = 25 m - Work = Force x Distance - Work = 1.176 N x 25 m - Work = 29.4 J

3. Calculate the power: - Power = Work / Time - Power = 29.4 J / 10 s - Power = 2.94 W

Therefore, the power of the driving force is 2.94 W and the work done is 29.4 J.

Note: The calculations are based on the given information and assumptions.