Tính lực tương tác giữa 2 điện tích q1=4.10^-6C và q2=-3.10^-6C cách nhau một 3cm đặt trong dầu hoả = 2

In which situation has the independent variable for the experiment been changed? check all that apply. changed from counting the number of duckweed at day 0 and day 14 to counting them every day changed from testing duckweed growth in beakers to testing duckweed growth in large outdoor tanks changed from testing the effect of ph on duckweed growth to testing the effect of light levels on duckweed growth changed from testing the effect of acid ph on duckweed growth to testing the effect of basic ph on duckweed growth

Simple machines can a. increase force only b. decrease force only c. increase or decrease force

If you place a magnet under a clear dish, and sprinkle iron fillings over it, above what part of the magnet will most of the fillings gather