In fig. 12-67a, a uniform 40.0 kg beam is centered over two rollers. vertical lines across the beam mark off equal lengths. two of the lines are centered over the rollers; a 10.0 kg package of tamales is centered over roller b. what are the magnitudes of the forces on the beam from (a) roller a and (b) roller b? the beam is then rolled to the left until the right-hand end is centered over roller b (fig. 12-67b). what now are the magnitudes of the forces on the beam from (c) roller a and (d) roller b? next, the beam is rolled to the right. assume that it has a length of 0.800 m. (e) what horizontal distance between the package and roller b puts the beam on the verge of losing contact with roller a?

When a neutrally charged atom loses an electron to another atom, the result is the creation of a. two charged atoms. b. two negatively charged atoms. c. two positively charged atoms. d. two neutrally charged atoms.

Ablock of mass m = 2.5 kg is attached to a spring with spring constant k = 710 n/m. it is initially at rest on an inclined plane that is at an angle of θ = 23° with respect to the horizontal, and the coefficient of kinetic friction between the block and the plane is μk = 0.19. in the initial position, where the spring is compressed by a distance of d = 0.16 m, the mass is at its lowest position and the spring is compressed the maximum amount. take the initial gravitational energy of the block as zero. a) what is the block's initial mechanical energy? b) if the spring pushes the block up the incline, what distance, l, in meters will the block travel before coming to rest? the spring remains attached to both the block and the fixed wall throughout its motion.

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.