DISCUSSION THREAD
Any questions??
Is there a way to convert from m to rad when multiplying the etheta term for velocity? The problem statement has R in m and the theta dot in rad/s
Please keep in mind that the radians representation of an angle is dimensionless; that is:
meters*radians/seconds = meters/seconds
Since theta is 0, does that mean the e_r and e_theta vectors point in the same directions as j and i respectively?
Stephen: Yes, that is correct.
Can we just say this conclusion or do we need to show a mathematical explanation?
Timothy: Not sure of your question here. If you are asking about the orientation of the two sets of unit vectors, then, yes, it is sufficient to just say that they are aligned, as Stephen describes above.
If you are asking something else, let me know.
For help converting polar to cartesian, I recommend going to page 52 in the lecture book.
With theta = 0, I don't think you need to do any complex converting.
Do we assume rdot and thetadot are constant?
Since we are not solving anything for acceleration vectors, why would you need this assumption for this problem?
Brayden is correct - you are not asked for information on acceleration, and therefore it is not you do not need to know any information of how r_dot and theta_dot change in time.
Since e^r and e^theta point in the same direction as the i and j unit vectors as discussed above, does that mean the velocity vector remains the same when converted to Cartesian since there is no projection occuring between the unit vectors?
There is no need for a coordinate transformation here on this problem due to the specific position of theta = 0.
There is a way to convert to cartesian from polar in this problem but since the theta is at 0, meaning the space shuttle is vertically above the coordinate origin, it makes the vertical and horizontal components of the velocity fairly easy to find without any conversion.
Keep theta's original positive orientation in mind when trying to find the direction of E_theta, since we are asked to find this vector when theta = 0.
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Wegovy is manufactured by Novo Nordisk.
Jakub Porzycki/NurPhoto via AP
Large-scale study finds Wegovy reduces risk of heart attack, stroke
BWH Communications
A trial study has found that injections of the weight-loss drug Wegovy reduced the risk of deaths from COVID-19 by about a third while also significantly reducing risk of death from cardiovascular disease or any other cause. The trial was led by Harvard-affiliated Brigham and Women’s Hospital. It was funded by Novo Nordisk, makers of Wegovy (the brand name of semaglutide).
From October 2018 through March 2023, researchers studied the effect of once-weekly Wegovy shots versus placebo on mortality in more than 17,000 participants with heart disease and overweight or obesity. The study showed that patients on Wegovy were about 15 percent less likely to die from cardiovascular disease and 23 percent less likely from other reasons as compared to those who took a placebo. Overall death rates in the group taking Wegovy were 19 percent lower compared to placebo.
“The trial started before COVID-19, and we never anticipated a global respiratory pandemic,” said corresponding author Benjamin M. Scirica, director of quality initiatives at BWH’s Cardiovascular Division and professor of medicine at Harvard Medical School.
“It is rare for a cardio-metabolic drug to modify non-cardiovascular outcomes,” Scirica added. “The fact that semaglutide reduced non-cardiovascular death, and in particular COVID-19-related deaths, was surprising. It opens up new avenues for exploring how this class of drugs may benefit patients.”
In the study, people taking Wegovy were just as likely to get COVID-19, but they had fewer serious illnesses or deaths related to COVID-19. The researchers do not know if the benefit of Wegovy is due to weight loss or other effects, but suggest that extra weight may be the greatest contributor to lower life expectancy. This result is from just one observation, albeit in a large, multinational study, so the findings need to be replicated. Further studies will explore potential mechanisms of action, and other studies of drugs in this class should provide additional data.
Results were published in the Journal of the American College of Cardiology.
Disclosures: Benjamin Scirica reports institutional research grants to Brigham and Women’s Hospital from Better Therapeutics, Merck, Novo Nordisk, and Pfizer; consulting fees from Allergan, Amgen, Boehringer Ingelheim, Better Therapeutics, Elsevier Practice Update Cardiology, Esperion, Hanmi, Lexicon, and Novo Nordisk; and equity in health [at] Scale, and Doximity. Novo Nordisk funded this study and was responsible for the study design in collaboration with the academic steering committee. They contributed to data collection, analysis, and interpretation and participated in the preparation and review of the manuscript in collaboration with the authors.
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Denise Pope, Stanford Graduate School of Education: (650) 725-7412, [email protected] Clifton B. Parker, Stanford News Service: (650) 725-0224, [email protected] Subscribe to Stanford Report
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The study showed that patients on Wegovy were about 15 percent less likely to die from cardiovascular disease and 23 percent less likely from other reasons as compared to those who took a placebo. Overall death rates in the group taking Wegovy were 19 percent lower compared to placebo.