if it takes 3.5 hours for the hogwarts express moving at a speed of 120 mi/hr to make it from platform 9 and 3/4 to hogwarts how
1 answer:
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Answer:
1.36
Explanation:
= Index of refraction of air = 1
= Index of refraction of plastic = ?
i = angle of incidence in air = 32.0° deg
r = angle of refraction in plastic = 23.0° deg
Using Snell's law
Sini =
Sinr
(1) SIn32.0 = Sin23.0
= 1.36
A) The mass of the continent is
B) The kinetic energy is 2016 J
C) The speed of the jogger should be 7.1 m/s
Explanation:
A)
The mass of the continent can be calculated as
where
is its density
V is its volume
We have to calculate its volume. We know that the continent is represented as a slab of side 5900 km (so its surface is 5900 x 5900, assuming it is a square) and depth of 26 km, so its volume is:
So, the mass of the continent is
B)
The kinetic energy of a body is given by
where
m is the mass of the body
v is its speed
For the continent, we have:
is the mass
is the speed
We have to convert the speed into SI units. we have:
1 cm = 0.01 m
So, the speed is
Therefore, the kinetic energy is
C)
Again, the kinetic energy of an object is
For the jogger in this problem, his mass is
m = 80 kg
And we want its kinetic energy to be equal to that of the continent, so
K = 2016 J
Re-arranging the equation for v, we find what speed the jogger needs to have this kinetic energy:
Learn more about kinetic energy here:
#LearnwithBrainly
Answer:
Terminal velocity of object = 12.58 m/s
Explanation:
We know that the terminal velocity is attained when drag force and gravitational force are of the same magnitude.
Gravitational force = mg = 80 * 9.8 = 784 N
Drag force =
Equating both, we have
So v = 12.58 m/s or v = -15.58 m/s ( not possible)
So terminal velocity of object = 12.58 m/s