A 9-year-old presents to the clinic with their grandparent….

A 9-year-old presents to the clinic with their grandparent. The patient is complaining that their “tummy” hurts. The grandparent is more concerned because they saw this rash: Upon further examination the nurse practitioner notes that the rash does not blanch and the patient has mild hematuria in their urine analysis. What is the appropriate diagnosis for this patient?

A cylindrical capacitor is made of two thin-walled concentri…

A cylindrical capacitor is made of two thin-walled concentric cylinders. The inner cylinder has radius r1 = 4.0 mm, and the outer one a radius r2= 8.0 mm. The common length of the cylinders is L = 150 m. What is the potential energy stored in this capacitor when a potential difference 4.0 V is applied between the inner and outer cylinder? (k = 1/4πε0 = 8.99 × 109 N ∙ m2/C2)