Một đòn bẩy dài 1,5m. G là trọng tâm. Đầu A đặt vật 10kg, điểm tựa O cách A 50cm. Đòn bẩy hợp với mặt đất 1 góc 30°. Tìm lực tác dụng vào đầu B để đòn bẩy cân bằng trong các trường hợp sau : a, lực F có phương ngang
b, lực F thẳng đứng
c, lực F vuông góc với AB

The ballistic pendulum was invented in 1742 by english mathematician benjamin robins. it consists of an initially stationary pendulum that moves after being struck by a bullet, and it is used to measure the original velocity of the bullet. the known variables are the bullet's mass m, the pendulum's mass m, and the height to which the block and bullet swing, determined by the length of the pendulum l and final angle θ. two principles of physics are necessary to solve for the bullet's original velocity. what are these principles? conservation of momentum and newton's third law conservation of energy and conservation of angular momentum grade summary deductions 0% potential 100% conservation of momentum and newton's second law. newton's second law and conservation of angular momentum. conservation of energy and newton's third law conservation of momentum and conservation of angular momentum. conservation of momentum and conservation of energy conservation of energy and newton's second law.

Acalorimeter uses the principle that thermal energy flows from hotter material to colder material until both reach the same

In the united states, tornadoes generally occur because of the freezing of ocean water underwater earthquakes meeting of cool and warm air masses shifting of warm and cool ocean currents