Question

Автомобиль массой 3,2т движется по горизонтальному пути со скоростью 54 км/ч. на каком расстоянии автомобиль остановится, если при торможении сила трения равна 45 кН?

Answer 1

F*S=m*v²/2   F=45*10^3   m=3.2*10^3   v=54/3.6=15 м/с

S=m*v²/(2*F)=8 м

Answer 2

Calculation of Stopping Distance

To calculate the stopping distance of a car, we need to consider the force of friction acting on the car during braking. The force of friction can be calculated using the equation:

Force of Friction (F) = Mass (m) x Acceleration (a)

In this case, the mass of the car is given as 3.2 tons, which is equivalent to 3200 kg. The acceleration can be calculated using the equation:

Acceleration (a) = Force of Friction (F) / Mass (m)

The force of friction is given as 45 kN, which is equivalent to 45000 N. Plugging in the values, we can calculate the acceleration:

Acceleration (a) = 45000 N / 3200 kg

Now, we can use the equation of motion to calculate the stopping distance. The equation of motion is:

Stopping Distance (s) = (Initial Velocity (v)^2) / (2 x Acceleration (a))

The initial velocity of the car is given as 54 km/h, which is equivalent to 15 m/s. Plugging in the values, we can calculate the stopping distance:

Stopping Distance (s) = (15 m/s)^2 / (2 x Acceleration (a))

Let's calculate the stopping distance using the given values.

Calculation:

1. Convert the mass of the car from tons to kilograms: - 1 ton = 1000 kg - 3.2 tons = 3.2 x 1000 kg = 3200 kg

2. Calculate the acceleration: - Acceleration (a) = 45000 N / 3200 kg = 14.0625 m/s^2

3. Calculate the stopping distance: - Stopping Distance (s) = (15 m/s)^2 / (2 x 14.0625 m/s^2) - Stopping Distance (s) = 225 m^2 / 28.125 m/s^2 - Stopping Distance (s) = 8 m

Therefore, the car will stop at a distance of 8 meters when the force of friction is 45 kN.