Physics is an integral part of medicine, from x-rays to medical imaging procedures such as Doppler ultrasound, echocardiography, magnetic resonance imaging, and ventilator operation. But is it necessary to become a doctor? The answer is no, but it does limit your options. Despite having entered medical school without ever taking a physics class, I am a permanent testimony that it is possible. However, physics is usually a mandatory class that you will have to take to apply to medical school.
Most American medical schools require one year of class credit (and lab work) to satisfy their admission boards. It is also favorably regarded as a Level A by UK medical schools (but not a necessity). However, there are usually not many physics-based questions on most medical school admission exams. In the MCAT, for example, the proportion is less than 10% (after taking into account the total average of each test section).
And it's almost similar for the others mentioned above. You don't need it to enter most English medical schools in Europe either (I'm an example of that). Interestingly, the attitude toward physics could be changing in the U. S.
Mount Sinai School of Medicine, for example, accepts HumED graduates in medicine without physics. They even did a study in which they showed that those students were no more likely to fail than those with a background in science (including physics). Therefore, there are several ways to become a doctor without taking physical. Physics is not a course in most MBBS US preclinical curricula.
However, when I went to an international medical school in Europe, I had to study physics. It constituted the credit of one semester in the first year (premed). Physiology relies heavily on it and you'll have to understand the common laws of physics to understand the functioning of various organ systems. You'll also dive into a little physics in radiology and oncology in your clinical rotations (more on that later).
Physics describes the behaviors of many of the phenomena we see in medicine. Things like blood flow, endocrine function, and oxygen diffusion that occur in various organ systems. Using mathematics as a model to demonstrate these actions is very important. Other places where it is important in medicine are imaging techniques. Things like CT scans, MRI scans and x-rays, etc.; each relies heavily on the rules and applications of physics to help diagnose patients' diseases and guide treatment plans. We know that physics describes a lot of what we see in medicine, but how do doctors (or medical students, etc.) actually use it? The quick answer? Most of the time, no.
We know that it is there and we see that it can be applied. But, in most aspects of the work of diagnosing diseases, it is not really necessary. The hard mathematics that describe the laws are shown to us as figures. These figures are recognized from memorization. Knowing what values show what, guides the diagnosis.
The same can be said of radiologists, oncologists and other specialists whose fields draw more direct parallels with physics as subject matter. Most of the time? They use machines that apply the laws to solve puzzles related to diagnosis or treatment. Obviously, patients may have more peace of mind believing that their doctors are physics experts (especially those who perform minimal-access surgeries), but the truth is that most doctors (and medical students) only have a superficial understanding at best. Nurses probably need even less physics than doctors. Often their role is more focused on providing care than on evaluating. Having a physics background in high school can make applicants for nursing courses more competitive (just like any hard science: chemistry, biology, etc.).
A more general response is similar to that of physicians; dependence on physics depends on function. Military trauma nurses who are expected to perform minor surgeries could benefit from a strong understanding of physics. Residential nurses, on the other hand, probably don't.I've already proven that you can get into medical school, graduate and become a doctor without even needing physics. The most important question is: is this a good idea? Probably for certain specialties; radiology, cardiology, oncology etc., it's not a good idea. Understanding physics in these areas of medicine is essential for routine daily work activities. But I would suggest that a good knowledge of physics is very essential to understand both the causes of pathology and the mechanisms of treatment (drug interactions etc.) as well.
So even if you can become a doctor without physics you may not be a particularly good or effective one if the specialty you have chosen requires it. You can be a doctor if you're bad at physics but not taking it (or not getting a good score) can significantly lower your options. Although there are several medical schools that do not request it as a prerequisite class, the vast majority (at least in the U. S.) do so. So if the medical school you plan to go to definitely requires it then keep your head down and keep working! Most medical schools agree on the basic elements of pre-education. Typically, the minimum course requirements include one year of biology, general chemistry (inorganic), organic chemistry, physics, and related laboratory work for each. In addition about two-thirds require an intensive English or writing course and about a quarter require calculus.
A small number of schools have no specific course requirements. In general medical schools do not publish a minimum GPA requirement.