# Tutor profile: Lilian C.

## Questions

### Subject: Physics (Newtonian Mechanics)

A person driving a car suddenly breaks. The car takes 4 seconds to come to a stop while traveling 20 meters at a constant acceleration. Can the speed of the car immediately before the breaks were applied be determined without first determining the car's acceleration?

Yes. To do so we can rearrange the kinematics equation that lacks acceleration as a variable: d= ((v1+v2)/2)*t. v1 is the variable we are trying to determine. v2 is 0 because the care came to a stop. t is 4s, and d is 20m. If we plug in those variables and solve for v1, then we can get the initial speed of the car, which is 10m/s.

### Subject: Pre-Calculus

Solve the equation sin^2x + sinx =0 for 0 </= theta </= 2pi

If sin^2x + sinx =0 , then you can factor out sinx to get sinx(sinx + 1)=0. Thus, sinx=0 or sinx+1=0. You can subtract 1 from both sides of the second equation to get: sinx= 0 or sinx=-1. Therefore, the solutions are then x = 0, pi, or 3pi/2, since the answer must be between 0 and 2pi.

### Subject: Anatomy

What anatomical feature allows a surgeon to distinguish the ileum from the other parts of the small intestines?

The small intestines are divided into three distinct sections: the duodenum, jejunum, and ileum (from proximal to distal). The proximal part of the duodenum starts where the stomach ends, and the distal part of the duodenum ends at the ligament of Treitz. The ligament of Treitz is the duodenojejunal junction and is fixed to the posterior wall of the abdomen. There is no distinctive jejunoileal junction. However, the way to distinguish between ileum or jejunum is that ileum has far more fat in its mesentery than the jejunum. There will be more complicated vascular arcades and shorter vasa recta than the jejunum. The ileum ends at the ileocecal junction where it is connected to the ascending colon.

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