Một lò xo có chiều dài tự nhiên là l0. Treo lò xo thẳng đứng rồi móc vào đầu dưới lò xo một vật có khối lượng m1 = 200 g, lò xo dài 11 cm. Thay vật m1 bằng vật m2 = 800 g, lò xo dài 17 cm. Lấy g = 10 m/s2. Tính chiều dài tự nhiên và độ cứng của lò xo?

The two stars in a certain binary star system move in circular orbits. the first star, alpha, has an orbital speed of 36 km/s. the second star, beta, has an orbital speed of 12 km/s. the orbital period is 137 d. a) what is the mass of the star alpha? b) what is the mass of the star beta?

You want to lose weight and have been trying to decide which type of fad diet is best for you. you ask your doctor, who responds that a. fad diets are a temporary fix but generally don't have any side effects b. fad diets can be used several times a year to maintain a healthy weight c. fad diets can be risky for your health and, in the long run, do not work d. fad diets should never be used one right after the other; there should be a break between them select the best answer from the choices provided. a b c d

The pilot of a helicopter hovers at an altitude of 1200 feet over a park. the angle of depression to the base of a statue is 17 degrees. the angle of depression to the nearest park exit, in line with the statue, is 14 degrees. to the nearest foot, what is the distance from the statue to the exit?