How much potential energy is stored in a spring that is stretched 15 cm by a force of 72 N?

Find the volume of the ellipsoid x^2+y^2+5z^2=36.

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

According to newtons universal law of gravitation, which would change the parh of the ball so it traces out widest curved path possible?