Because of your expert physics skills, you have been hired as an analyst in a court case involving an automobile accident. The a
1 answer:
Answer:
v = 91.8 Km / h
Explanation:
We must start this exercise at the end, let's look for the lighter car acceleration (B), for this we use Newton's second law
fr = m a
a = fr / m
fr = μ N
N-W = 0
Let's replace
a = μ m g / m
a = μ g
a = 0.8 9.8
a = 7.84 m / s²
As the car B after the crash reached an initial velocity vo₀₂ and at the end of the fine speed zero, let us use kinematics
v² = v₀₂² - 2 a x
0 = v₀₂² - 2 a x
v₀₂ = 2 a x₂
v₀₂ = √ (2 7.84 26)
v₀₂ = 20.19 m / s
Let's perform the same procedure for car A, the acceleration is the same as it does not depend on the mass of the vehicles
v₀₁ = √ 2 a x₁
v₀₁ = √ (2 7.84 19)
v₀₂ = 17.36 m / s
Now let's use moment conservation, where the system is the two vehicles
Initial before crash.
p₀ = M v₁ + 0
After the crash
= M v₀₁ + m v₀₂
p₀ =
M v₁ = M v₀₁ + m v₀₂
v₁ = v₀₁ + m / M v₀₂
v₁ = 17.36 + 1841/3000 20.19
v₁ = 20.75 m / s
This is the speed of car 1 (A) just before the crash, now let's look for the speed when I apply the brakes the initial speed (v)
v₁² = v² - 2 a x₁
v = √ (v₁² + 2 a x₁)
v = √ (20.75² + 2 7.84 14)
v = 25.50 m / s
v = 25.50 m / s (1km / 1000m) (3600s / 1h)
v = 91.8 Km / h
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Answer:
i) The period of the particle is 0.3 seconds
ii) The angular velocity is approximately 20.94 rad/s
iii) The linear velocity is approximately 1.047 m/s
iv) The centripetal acceleration is approximately 6.98 m/s²
Explanation:
The given parameters are;
The number of revolution of the particle, n = 800 revolution
The time it takes the particle to make 800 revolutions = 4 minutes
The dimension of the circle = 5 cm = 0.05 m
Given that the dimension of the circle is the radius of the circle, we have;
i) The period of the particle, T = The time to complete one revolution
T = 1/(The number of revolutions per second)
∴ T = 1/(800 rev/(4 min × 60 s/min)) = 3/10 s
The period, T = 3/10 seconds = 0.3 seconds
ii) The angular velocity, ω = Angle covered/(Time)
800 revolutions in 4 minutes = Angle of (800 × 2·π) in 4 minutes
∴ ω = (800 × 2·π)/(4 × 60) = 20·π/3
The angular velocity, ω = 20·π/3 rad/s ≈ 20.94 rad/s
iii) The linear velocity, v = r × ω
∴ The linear velocity, v = 0.05 m × 20·π/3 rad/s = π/3 m/s ≈ 1.047 m/s
iv) The centripetal acceleration, = v²/r
∴ The centripetal acceleration, = (π/3)²/(0.05) = 20·π/9
The centripetal acceleration, = 20·π/9 m/s² ≈ 6.98 m/s²