Question

Троллейбус массой 4 т, трогаясь с места, приобрел на пути 50 м скорость 10 м/с. Найдите коэффициент трения, если сила тяги равна 14 кН

Answer 1

S=V^2/2*a
a=V^2/2*S=10^2/2*50=1 м/с2
m*a=F-u*m*g
u=(F-m*a)/m*g=(14000-4000*1)/4000*10=0,25

Answer 2

Calculating the Coefficient of Friction

To calculate the coefficient of friction, we can use the formula:

Coefficient of Friction (μ) = (Force of Friction) / (Normal Force)

First, let's calculate the force of friction using the given information.

The force of friction can be calculated using the equation:

Force of Friction = Mass * Acceleration

Given: - Mass (m) = 4 tons = 4000 kg - Distance (s) = 50 m - Initial velocity (u) = 0 m/s - Final velocity (v) = 10 m/s

Using the equation: v^2 = u^2 + 2as

We can solve for acceleration (a) using the given values of distance and final velocity.

Calculating Acceleration

Using the equation: v^2 = u^2 + 2as

Where: - v = final velocity = 10 m/s - u = initial velocity = 0 m/s - s = distance = 50 m

We can solve for acceleration (a).

v^2 = u^2 + 2as
(10 m/s)^2 = (0 m/s)^2 + 2 * a * 50 m
100 m^2/s^2 = 100 m^2/s^2 + 100a
100a = 100 m^2/s^2
a = 1 m/s^2

So, the acceleration (a) is 1 m/s^2.

Calculating Force of Friction

Now, we can calculate the force of friction using the formula: Force of Friction = Mass * Acceleration

Given: - Mass (m) = 4000 kg - Acceleration (a) = 1 m/s^2

Force of Friction = 4000 kg * 1 m/s^2
Force of Friction = 4000 N

Calculating the Coefficient of Friction

Now that we have the force of friction, we can calculate the coefficient of friction using the formula: Coefficient of Friction (μ) = (Force of Friction) / (Normal Force)

Given: - Force of Friction = 4000 N - Force of Traction = 14 kN = 14000 N

Coefficient of Friction (μ) = 4000 N / 14000 N
Coefficient of Friction (μ) = 0.2857

So, the coefficient of friction is approximately 0.2857.