Athin rod (length = 2.97 m) is oriented vertically, with its bottom end attached to the floor by means of a frictionless hinge. the mass of the rod may be ignored, compared to the mass of the object fixed to the top of the rod. the rod, starting from rest, tips over and rotates downward. (a) what is the angular speed of the rod just before it strikes the floor? (hint: consider using the principle of conservation of mechanical ) what is the magnitude of the angular acceleration of the rod just before it strikes the floor?

Follow these directions and answer the questions. 1. set up the ripple tank as in previous investigations. 2. bend the rubber tube to form a "concave mirror" and place in the ripple tank. the water level must be below the top of the hose. 3. generate a few straight pulses with the dowel and observe the reflected waves. do the waves focus (come together) upon reflection? can you locate the place where the waves meet? 4. touch the water surface where the waves converged. what happens to the reflected wave? 5. move your finger twice that distance from the hose (2f = c of c, center of the curvature) and touch the water again. does the image (the reflected wave) appear in the same location (c of c)? you may have to experiment before you find the exact location. sometimes it is hard to visualize with the ripple tank because the waves move so quickly. likewise, it is impossible to "see" light waves because they have such small wavelengths and move at the speed of light. however, both are examples of transverse waves and behave in the same way when a parallel wave fronts hit a curved surface.

Which statements did both aristotle and ptolemy assume? check all that apply.

Aforce is a vector quantity because it has both?