Một ô tô chuyển động từ A đến B với tốc độ 30m/s rồi lập tức quay lại A với tốc độ 20m/s. Tính tốc độ trung bình trên cả đoạn đi và về

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".

Asimple electrochemical cell contains two electrodes.

Happiness is to senipah as 517768399 is to what?