I would say C. is the answer.
Answer: D
Explanation: D is the most reasonable answer because it's always good to plan ahead for anything, so if you were to plan ahead for future obstacles, then you can overcome them.
Sun-earth-moon in a straight line. Earth in the 'middle'.
Answer:
* in a tube with both ends open
λ = 2L / n n = 1, 2, 3,…
* tube with one end open and the other closed.
λ = 4L / n n = (2n ’+ 1 )
Explanation:
When a sound wave enters a pipe, a resonance process occurs, whereby only some wavelengths can occur.
* in a tube with both ends open
in this case there are maximums at each end, so if the length of the had is L
λ = 2L 1st harmonic
λ = 2 L / 2 2nd harmonic
λ = 2L / 3
λ = 2L / n n = 1, 2, 3,…
* In the case of a tube with one end open and the other closed.
At the open end there is a belly and at the closed end a node
λ = 4L 1st harmonic
λ = 4L / 3 3rd harmonic
λ = 4L / 5
λ = 4L / n n = 1, 3, 5,… odd
n = (2n ’+ 1 ) where n’ are all integers
Answer:
34.3 m/s
Explanation:
Newton's Second Law states that the resultant of the forces acting on the car is equal to the product between the mass of the car, m, and the centripetal acceleration
(because the car is moving of circular motion). So at the top of the hill the equation of the forces is:

where
(mg) is the weight of the car (downward), with m being the car's mass and g=9.8 m/s^2 is the acceleration due to gravity
R is the normal reaction exerted by the road on the car (upward, so with negative sign)
v is the speed of the car
r = 0.120 km = 120 m is the radius of the curve
The problem is asking for the speed that the car would have when it tires just barely lose contact with the road: this means requiring that the normal reaction is zero, R=0. Substituting into the equation and solving for v, we find:
