Author Question: A recent announcement indicated that magnetic motors can be used to cool refrigerators. In the ... (Read 15 times)

clmills979 · **on:** Jul 28, 2018

A recent announcement indicated that magnetic motors can be used to cool refrigerators. In the method, a gadolinium-based warms and cools off in response to application of a magnetic field. The gadolinium rotating wheel is the only moving part.

Why might this be a breakthrough?

Question 2

A car drives down one hill and up another maintaining constant speed (the road is a V-shape with a rounded bottom).

What can be said of the acceleration of the car along the left side of the V halfway down? What can be said of the acceleration of the car along the right side of the V halfway up? Where on the track is the acceleration the greatest? Explain.

Ahnyah · **Reply #1 on:** Jul 28, 2018

Answer to Question 1

Moving parts involve friction. Elimination of friction reduces waste of energy. It
remains to be seen whether this is a breakthrough.

Answer to Question 2

If that car has the same speed along the left side of the V, it must have an
acceleration of zero (because there is no change in speed or direction). Likewise, along the
straight right side of the V, it also has an acceleration of zero.
If the speed never changes, then the only place there can be an acceleration is at the bottom,
where the direction is changing. A change in direction means a change in the velocity.