Answer:
t = 2 seconds
Explanation:
In 2nd question, the question is given the attached figure.
Initial speed of the bus, u = 0
Acceleration of the bus, a = 8 m/s²
Final speed, v = 16 m/s
We need to find the time taken by the car to reach the stop. Acceleration of an object is given by :
t is time taken
The bus will take 2 seconds to reach the stop.
1) Medium "b" has more optical density
2) Light must hit the interface between the two mediums perpendicularly
Explanation:
1)
Refraction occurs when light propagates from a medium into a second medium.
The optical density of a medium is given by its index of refraction, which is defined as:
where
c is the speed of light in a vacuum
v is the speed of light in a medium
Higher index of refraction means higher optical density, and light propagater slower into a medium with higher optical density.
In this problem, light propagates faster through medium "a" than medium "b": this means that medium "a" has lower refractive index of medium "b", and so "b" has more optical density.
2)
We can answer this part by referring to Snell's law, which gives the relationship between the direction of the incident ray and of the refracted ray when light passes through the interface between two media:
where
are the index of refraction of the two mediums
are the angle of incidence and of refraction (the angle that light makes with the normal to the surface in medium 1 and medium 2)
Here we want the direction of propagation of the light ray not to change: this means that it must be
(1)
However, here we have two mediums "a" and "b" with different index of refraction, so
Therefore the only angle that can satisfy eq.(1) is
So, the light must hit the surface perpendicular to the interface between the two mediums.
Learn more about refraction:
#LearnwithBrainly
Answer:
x = 76.5 m
Explanation:
Let's use Newton's second law at the point of contact between the wheel and the floor.
fr = m a
fr = miy N
N-W = 0
N = W
μ mg = m a
a = miu g
a = 0.600 9.8
a = 5.88 m / s²
Having the acceleration we can use the kinematic relationships to find the distance
² = v₀² + 2 a x
= 0
x = -v₀² / 2 a
Acceleration opposes the movement by which negative
x = - 30²/2 (-5.88)
x = 76.5 m