how many revolutions are completed by a top spinning with a constant angular velocity of 3pi radians during a 20 sec time interv
1 answer:
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2000J
Explanation:
Given parameters:
Extension = 0.5m
Spring constant = 16000N/m
Unknown:
Energy stored in the bow string = ?
Solution:
The energy stored in a bow string is an elastic potential energy.
It can be calculated using the expression below;
Elastic energy = K e²
Where k is the spring constant
e is the extension
Input the parameters;
Elastic energy = K e²
= x 16000 x 0.5²
= 2000J
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Potential energy brainly.com/question/10770261
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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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