Apply conservation of angular momentum:
L = Iw = const.
L = angular momentum, I = moment of inertia, w = angular velocity, L must stay constant.
L must stay the same before and after the professor brings the dumbbells closer to himself.
His initial angular velocity is 2π radians divided by 2.0 seconds, or π rad/s. His initial moment of inertia is 3.0kg•m^2
His final moment of inertia is 2.2kg•m^2.
Calculate the initial angular velocity:
L = 3.0π
Final angular velocity:
L = 2.2w
Set the initial and final angular momentum equal to each other and solve for the final angular velocity w:
3.0π = 2.2w
w = 1.4π rad/s
The rotational energy is given by:
KE = 0.5Iw^2
Initial rotational energy:
KE = 0.5(3.0)(π)^2 = 14.8J
Final rotational energy:
KE = 0.5(2.2)(1.4)^2 = 21.3J
There is an increase in rotational energy. Where did this energy come from? It came from changing the moment of inertia. The professor had to exert a radially inward force to pull in the dumbbells, doing work that increases his rotational energy.
The correct answer is - C. Crustal plates, crustal plates.
The movement of the crustal plates of the Earth is the reason why the geologic processes are occurring on our planet. With their movement, the crustal plates manage to create lot of pressure, open up gaps for the magma from the mantle, as well as make adjustments deeper into the ground.
Because of the adjustments deep into the ground, or rather the crust, lot of force is released, manifested as strong and very quick vibrations, better known as earthquakes.
The gaps that are opening between the plates let the magma reach the surface, thus enabling the volcanic activities on the planet.
The pressure from the plates' collision makes the land lift up slowly, and over time a mountain range starts to form because of the continuous lifting up of the area.
Answer:
A solenoid field is increased with the increase in the current flow through the coil.
Explanation:
A solenoid is a current carrying coil with a significant number of loops. It works like an electromagnet inside which, a uniform and strong magnetic field is created. The magnetic field outside the solenoid field is nearly zero but not exactly zero.
While experimenting with the solenoid, scientists came to know that the magnetic field generated by the solenoid increases with the increase in the current, flowing through the solenoid.
The magnetic field works strongly around the arena of coil. The field changes its direction only near the ends and gets weak. Else its uniform throughout the loops.
The magnetic field inside the solenoid can be formulated as,
Where,
B = Magnetic field generated by the solenoid
= Constant
I = Current flowing through the loops of the solenoid
Answer:
The Big Bang Theory is the leading explanation about how the universe began. At its simplest, it says the universe as we know it started with a small singularity, then inflated over the next 13.8 billion years to the cosmos that we know today.
Explanation: Hope this help! :)
