Answer:
The most correct option is;
B. 10 km
Explanation:

Where:
y = Distance between the two headlights
d = Aperture of observers eye
λ = Wavelength of light
L = Distance between the observer and the headlight
Therefore, from the above solution, the distance between the observer and the headlights is 9386.066 km which is approximately 10 km.
Also we have
sinθ = y/L = 1.22 (λ/d)
sinθ = 1.22×10⁻⁴ rad
Answer:
0.22 m
Explanation:
We are told that the driver can survive an acceleration of 50g only if the collision lasts no longer than 30 ms. So,

The acceleration is

where the negative sign is due to the fact that this is a deceleration, since the driver comes to a stop in the collision.
First of all, we can find what the initial velocity of the car should be in this conditions by using the equation:

And since the final velocity is zero, v=0, and solving for u,

And now we can find the corresponding distance travelled using the equation:

Time=speed/acceleration
Gravitaional Acceleration=9.8 m/s^2
Speed=24.5 m/s
Time=24.5/9.8=2.5 s
Answer:
height of the water rise in tank is 10ft
Explanation:
Apply the bernoulli's equation between the reservoir surface (1) and siphon exit (2)

-------(1)
substitute 
0ft/s for V₁, 20ft for (z₁ - z₂) and 32.2ft/s² for g in eqn (1)


Applying bernoulli's equation between tank surface (3) and orifice exit (4)

substitute

0ft/s for V₃, h for z₃, 0ft for z₄, 32,2ft/s² for g

At equillibrium Fow rate at point 2 is equal to flow rate at point 4
Q₂ = Q₄
A₂V₂ = A₃V₃
The diameter of the orifice and the siphon are equal , hence there area should be the same
substitute A₂ for A₃
for V₂
for V₄
A₂V₂ = A₃V₃

Therefore ,height of the water rise in tank is 10ft