Question

Тело массой m=4кг движется прямолинейно равномерно под действием постоянной силы F, составляющей угол альфа = 45 градусов с горизонтом. Определите коэффициент трения между телом и горизонтальной поверхностью, по которой оно движется, если механическая работа, совершенная силой F на пути s=5.2м, равна 48Дж. Ответ: 0.3

Answer 1

M=4 кг                   Работа:  А=Fтр.Scos45°;     cos45°=0,71;
α=45°                                                                   Fтр=μmg; тогда.
g=10 м/с                              А=μmgS*0,71 ⇒      μ=A/mgS*0,71;
s=5,2 м                                μ=48/4*10*5,2*0,71=0,33;
A=48 Дж                Ответ: μ=0,33
___________
μ-?

Answer 2

Given information:

- Mass of the body, m = 4 kg - Angle made by the force with the horizontal, α = 45 degrees - Mechanical work done by the force, W = 48 J - Distance traveled by the body, s = 5.2 m

Approach to solve the problem:

1. Convert the angle from degrees to radians. 2. Calculate the work done by the force using the formula: W = F * s * cos(α) 3. Calculate the magnitude of the force using the formula: F = W / (s * cos(α)) 4. Calculate the frictional force using the formula: Frictional force = F - Normal force 5. Calculate the normal force using the formula: Normal force = m * g 6. Calculate the coefficient of friction using the formula: Coefficient of friction = Frictional force / Normal force

Calculation:

1. Convert the angle from degrees to radians: α = 45 degrees = 45 * π / 180 radians = π / 4 radians

2. Calculate the work done by the force: W = F * s * cos(α) 48 J = F * 5.2 m * cos(π / 4) F = 48 J / (5.2 m * cos(π / 4)) F ≈ 9.828 N

3. Calculate the frictional force: Frictional force = F - Normal force Frictional force = 9.828 N - Normal force

4. Calculate the normal force: Normal force = m * g Normal force = 4 kg * 9.8 m/s^2 Normal force = 39.2 N

5. Calculate the coefficient of friction: Coefficient of friction = Frictional force / Normal force Coefficient of friction = (9.828 N - 39.2 N) / 39.2 N Coefficient of friction ≈ -0.75

Answer:

The coefficient of friction between the body and the horizontal surface is approximately -0.75.