A slingshot fires a pebble from the top of a building at a speed of 10.3 m/s. The building is 38.4 m tall. Ignoring air resistance, find the speed with which the pebble strikes the ground when it is fired vertically straight up.

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

The two required components for a generator are

Explain why electric current cannot exist if a current doesn't have a voltage source.