trên đường thẳng AB, cùng một lúc xe ô tô 1 khởi hành từ A đến B với v = 72km/h. Xe ô tô thứ 2 từ B đi về A với v = 45 km/h. Biết AB cách nhau 80 km. Lập phương trình chuyển động của mỗi xe trên cùng một hệ quy chiếu.

Two 1.20-m nonconducting wires meet at a right angle. one segment carries + 2.50 µc of charge distributed uniformly along its length, and the other carries - 2.50 µc distributed uniformly along it, as shown in fig. 21.50. ( a. find the magnitude and direction of the electric field these wires produce at point p, which is 60.0 cm from each wire. ( b. if an electron is released at p, what are the magnitude and direction of the net force that these wires exert on it?

Energy flows from the producer level to the level. is called

Cathy is pedaling down a steep hill on her bicycle and wants to be able to coast up the next hill, which is 25 meters high, without pedaling. cathy and her bicycle have a mass of 75 kg. assuming her bicycle is 100% efficient, what would her speed have to be?