Water that flows from behind a large dam can cause machines to produce electricity. What change take place? Heat energy into mec
2 answers:
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Answer:
The answer is β=0,85 rads
Explanation:
As the ladder is leaning against the building, we can imagine there´s a triangle where 20ft is the hypotenuse and 15ft is the maximum vertical distance between the ladder and the ground, it means, the leg opposite to β which is the angle we need
Let β(betha) be the angle between the ladder and the ground
We also know that
In this case we will need to find β, this way:
Then β=48,6°
We also have that 2πrads is equal to 360°, in this way we find how much β is in radians:
then we find β=0,85rads
1) The mass of the continent is
2) The kinetic energy of the continent is 274.8 J
3) The speed of the jogger must be 2.76 m/s
Explanation:
1)
The continent is a slab of side 5900 km (so the surface is 5900 x 5900, assuming it is a square) and depth 26 km, therefore its volume is:
The mass of the continent is given by
where:
is its density
is its volume
Substituting, we find the mass:
2)
To find the kinetic energy, we need to convert the speed of the continent into m/s first.
The speed is
v = 1.6 cm/year
And we have:
1.6 cm = 0.016 m
So, the speed is
Now we can find the kinetic energy of the continent, which is given by
where
is the mass
is the speed
Substituting,
3)
The jogger in this part has the same kinetic energy of the continent, so
K = 274.8 J
And its mass is
m = 72 kg
We can write his kinetic energy as
where
v is the speed of the man
And solving the equation for v, we find his speed:
Learn more about kinetic energy:
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