At what distance from a convex lens must an object be to get a virtual image?
-at a focal point
-at more than twice the focal length
-greater than the focal length but less than twice the focal length
-at a distance less than the focal length

Phase changes are chemical changes. true or false

For which pair of objects would adding the same a

During a medieval siege of a castle, the attacking army uses a trebuchet to hurl heavy stones at the castle walls. if the trebuchet launches the stones with a velocity of at an angle of 50.0°, (a) how long does it take the stone to hit the ground? (b) what is the maximum distance that the trebuchet can be from the castle wall to be in range? (c) how high will the stones go? show all your work.