This will take me a little bit let me research :)
Answer:
The Spanish philosopher George Santayana wrote, “those who cannot remember the past are condemned to repeat it.” When it comes to climate change, repeating the past is a luxury we can’t afford. If partisan politics continues to derail policy or if denial continues to win over science, it will mean irreversible changes to our planet. Future generations will look at ours as the one that didn’t have the courage to act, rather than the one that recognized the fierce urgency of the moment and met it head on.
With this in mind, we’ve created a climate change timeline highlighting the evolution of science, the intrusion of denial, and the sluggishness of policy over the past 200 years. Let’s learn from the mistakes of the past, so we can make tomorrow a brighter—but not hotter—future.
Answer:
When she stretches her arms out,<em> B) her angular speed ω increases due to her moment of inertia decreasing</em>
Explanation:
The angular momentum of a rotating object is defined as the product of its moment of inertia and angular speed.
<em>L = I ω</em>
<em>where</em>
- <em>L is the angular momentum</em>
- <em>I is the moment of inertia</em>
- <em>ω is the angular speed</em>
<em />
According to the principle of conservation of angular momentum, if there is no external torque, angular momentum of the skater must remain conserved. If the initial and final moment of inertia is <em>I_i and I_f </em>while corresponding angular velocities are <em>ω_i and ω_f , </em>then the principle of conservation of angular momentum can be expressed as the following equation:
<em>(I_f) (ω_f) = (I_i) (ω_i)</em>
<em>ω_f / ω_i = I_i / I_f</em>
<em />
From the expression above, we can see that if the moment of inertia decreases, angular velocity would increase to conserve angular momentum of the skater.
Therefore, When she stretches her arms out,<em> her angular speed ω increases due to her moment of inertia decreasing.</em>
Because it is acted upon by balanced forces.
Toy cars use a variety of mechanisms to make them go, but they all store up potential energy. Although the elastic material inside is usually steel and not rubber, the principle is the same. By changing the shape of the material (usually a coil of metal) energy is stored and then released as motion.
