Câu 4: Phương trình chuyển động của một chất điểm trong hệ tọa độ Oxy là x =2t (cm); y = 3t2 (cm). Khoảng cách từ chất điểm đến gốc tọa độ tại thời điểm t = 2s là

Alead ball is dropped into a lake from a diving board 5m above the water . it hits the water with a certain velocity and then sink with constant velocity in bottom . it reaches the bottom 5 second after it is dropped if g= 10m/s2 . find depth of the lake and average velocity of the ball ?

The sun’s mass is 2.0×10^ 30 kg, its radius is 7.0×10 5 km, and it has a rotational period of approximately 28 days. if the sun should collapse into a white dwarf of radius 3.5×10 3 km, what would its period be if no mass were ejected and a sphere of uniform density can model the sun both before and after?

What describes the particles in a liquid