Question

обчислити силу тертя при гальмуванні автомобиля якщо його маса 1.5т, кофіціент тертя ковзання 0.7. Який гальмовий шлях та час його гальмування , якщо автомоюіль їхав зі швидкістю 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 Frictional Force

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

Frictional force = coefficient of friction × normal force

Given: - Mass of the car (m) = 1.5 tons = 1500 kg - Coefficient of friction (μ) = 0.7

The normal force can be calculated using the formula: Normal force = mass × acceleration due to gravity

The acceleration due to gravity (g) is approximately 9.81 m/s^2.

Let's calculate the normal force first: Normal force = 1500 kg × 9.81 m/s^2

Now, we can calculate the frictional force: Frictional force = 0.7 × (1500 kg × 9.81 m/s^2)

Braking Distance and Time

To calculate the braking distance and time, we can use the following formulas:

Braking distance = (initial velocity^2) / (2 × deceleration) Time of braking = (final velocity - initial velocity) / deceleration

Given: - Initial velocity (u) = 72 km/h - Initial velocity in m/s = 20 m/s (since 1 km/h = 1000 m/3600 s) - Final velocity (v) = 0 m/s (since the car comes to a stop) - Deceleration (a) = frictional force / mass

Let's calculate the deceleration first: Deceleration = Frictional force / mass

Now, we can calculate the braking distance: Braking distance = (20 m/s)^2 / (2 × deceleration)

And the time of braking: Time of braking = (0 m/s - 20 m/s) / deceleration

Let's calculate these values.