Question

Автомобиль затормозил при скорости 36 км/ч коэффициент трения 0,4, найти время торможения путь и ускорения. заранее спасибо

Answer 1

Дано  k=0,4     V=10 м/с     S-?
 Тормозной путь вычисляется по формуле 
S =V^2/2*k*g=10*10/2*0,4*10=100/8=12,5 м
 найдем ускорение   a = -k*m*g/m=-0,4*10= -4м/с2
найдем время торможения  t= -V0/a= 10/4=2,5 c

Answer 2

Calculation of Stopping Time, Distance, and Acceleration

To find the stopping time, distance, and acceleration of a car that brakes at a speed of 36 km/h with a coefficient of friction of 0.4, we can use the following formulas:

1. Stopping Time: - The stopping time can be calculated using the formula: stopping time = speed / acceleration. - In this case, the speed is given as 36 km/h, which needs to be converted to m/s. - The conversion factor from km/h to m/s is 1 km/h = 0.2778 m/s. - Therefore, the speed in m/s is 36 km/h * 0.2778 m/s = 10 m/s. - Now, we can calculate the stopping time using the formula: stopping time = 10 m/s / acceleration.

2. Stopping Distance: - The stopping distance can be calculated using the formula: stopping distance = (speed^2) / (2 * acceleration). - In this case, the speed is given as 36 km/h, which needs to be converted to m/s. - Therefore, the speed in m/s is 36 km/h * 0.2778 m/s = 10 m/s. - Now, we can calculate the stopping distance using the formula: stopping distance = (10 m/s)^2 / (2 * acceleration).

3. Acceleration: - The acceleration can be calculated using the formula: acceleration = coefficient of friction * gravitational acceleration. - The coefficient of friction is given as 0.4. - The gravitational acceleration is approximately 9.8 m/s^2. - Therefore, the acceleration is 0.4 * 9.8 m/s^2.

Let's calculate the stopping time, distance, and acceleration using the given values:

1. Stopping Time: - Speed: 36 km/h = 10 m/s. - Acceleration: 0.4 * 9.8 m/s^2 = 3.92 m/s^2. - Stopping time = 10 m/s / 3.92 m/s^2 = 2.55 seconds.

2. Stopping Distance: - Speed: 36 km/h = 10 m/s. - Acceleration: 0.4 * 9.8 m/s^2 = 3.92 m/s^2. - Stopping distance = (10 m/s)^2 / (2 * 3.92 m/s^2) = 12.76 meters.

3. Acceleration: - Coefficient of friction: 0.4. - Gravitational acceleration: 9.8 m/s^2. - Acceleration = 0.4 * 9.8 m/s^2 = 3.92 m/s^2.

Therefore, the calculated values are as follows: - Stopping time: 2.55 seconds. - Stopping distance: 12.76 meters. - Acceleration: 3.92 m/s^2.

Please note that these calculations are based on the given values and assumptions.