Answer:
The time where the avergae speed equals the instaneous speed is T/2
Explanation:
The velocity of the car is:
v(t) = v0 + at
Where v0 is the initial speed and a is the constant acceleration.
Let's find the average speed. This is given integrating the velocity from 0 to T and dividing by T:
v_ave = v0+a(T/2)
We can esaily note that when <u><em>t=T/2</em></u><u><em> </em></u>
v(T/2)=v_ave
Now we want to know where the car should be, the osition of the car is:
Where x_A is the position of point A. Therefore, the car will be at:
<u><em>x(T/2) = x_A + v_0 (T/2) + (1/8)aT^2</em></u>
Answer:
D) equal to the flux of electric field through the Gaussian surface B.
Explanation:
Flux through S(A) = Flux through S (B ) = Charge inside/ ∈₀
Answer:
She must stop the car before interception, distance traveled 12.66 m
Explanation:
We will take all units to the SI system
Vo = 48Km / h (1000m / 1Km) (1h / 3600s) = 13.33 m / s
V2 = 70 Km / h = 19.44 m / s
We calculate the distance traveled before stopping
X = Vo t + ½ to t²
Time is what it takes traffic light to turn red is t = 2.0 s
X = 13.33 2 + 1.2 (-7) 2²
X = 12.66 m
It stops car before reaching the traffic light turning to red
Let's analyze what happens if you accelerate, let's calculate the acceleration of the vehicle
V2 = Vo + a t2
a = (V2-Vo) / t2
a = (19.44-13.33) /6.6
a = 0.926 m / s2
This is the acceleration to try to pass the interception, now let's calculate the distance it travels in the time the traffic light changes from yellow to red (t = 2.0 s)
X = Vo t + ½ to t²
X = 13.33 2 + ½ 0.926 2²
X = 28.58 m
Since the vehicle was 30 m away, the interception does not happen
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