Question

Обчислити силу тертя при гальмуванні автомобіля, якщо його маса 1,5т, коефіцієнт тертя дорівнює 0,7. Який гальмівний шлях та час його гальмування, якщо автомобіль мав швидкість 72 км/ год ?

Answer 1

Ответ:

F=10500H;

t≈2,85c

S≈28,57м

Объяснение:

m=1,5т=1500кг

ŋ=0,7

V⁰=0

V=72км/год=20м/с

F;t;S-?

F=ŋ×N=ŋ×m×q=0,7×1500×10=10500H

N=m×q

a=F/m=10500/1500=7м/с²

t=(V-V⁰)/a=(20-0)/7≈2,85c

S=(V²-Vo²)/2×a=(20²-0²)/2×7=400/14≈28,57м

Answer 2

Calculating Friction Force during Braking

To calculate the friction force during braking, we can use the formula:

Friction Force = Coefficient of Friction × Normal Force

Given: - Mass of the car (m) = 1.5 tons = 1500 kg - Coefficient of friction (μ) = 0.7 - Speed of the car (v) = 72 km/h

First, we need to calculate the normal force acting on the car, which is equal to the gravitational force acting on the car.

The formula for gravitational force is: Gravitational Force = Mass × Acceleration due to Gravity

Using the value of acceleration due to gravity (g) as 9.81 m/s^2, we can calculate the gravitational force acting on the car.

Then, we can calculate the friction force using the formula mentioned above.

Calculating Braking Distance and Time

To calculate the braking distance and time, we can use the equations of motion under constant deceleration.

The initial speed of the car (u) is 72 km/h, and the final speed (v) is 0 (since the car comes to a stop).

The deceleration (a) can be calculated using the formula: Deceleration = (Final Speed^2 - Initial Speed^2) / (2 × Distance)

Using the calculated deceleration, we can then find the braking distance using the equation: Distance = (Initial Speed^2 - Final Speed^2) / (2 × Deceleration)

The braking time can be calculated using the formula: Time = (Final Speed - Initial Speed) / Deceleration

Let's proceed with the calculations.