Physics Answers

Compare the mirror equation with the thin lens equation. Discuss similarities and differences, especially the sign conventions for the quantities involved.

A thin converging lens is moved closer to a nearby object. Does the real image formed change (a) in position, (b) in size? If yes, describe how.

Two lenses, one converging with focal length 20.0 cm and one diverging with focal length -10.0 cm are placed 25.0 cm apart. An object is placed 60.0 cm in front of the converging lens. Determine (a) the position and (b) the magnification of the final image formed. (c) Sketch a ray diagram for this system.

A diverging lens with f = –36.5 cm is placed 14.0 cm behind a converging lens with f = 20 cm. Where will an object at infinity be focused?

A stamp collector uses a converging lens with focal length 28 cm to view a stamp 16 cm in front of the lens. (a)Where is the image located? (b) What is the magnification?

The wave function associated with standing waves established in a 4.00 m long string is

y = 0.00500 sin(πx)cos(150πt) where x and y are in meters and t is in seconds.

(a) How many half-wavelengths does this pattern exhibit?

(b) What is the fundamental frequency of vibration of the string (in Hz)?

c) If the original frequency is held constant and the tension in the string is increased by a factor of 4, how many half wavelengths are present in the new pattern?

  A sharp image is located 391 mm behind a 215-mm focal- length converging lens. Find the object distance (a) using a ray diagram, (b) by calculation.

A 1.4 m long thin uniform rod is pivoted at one point so that it oscillates like a physical pendulum. Compare the angular frequency of this physical pendulum with a simple pendulum of the same length, both oscillating near the earth’s surface.

The period of oscillation of a 7.49-kg body is suspended at a point 0.22 m from its center of mass is 6.45 s. Find the moment of inertia about an axis through the pivot point of the body. Round off your final answer to two decimal places.

A pendulum has a string of length 0.58 meters supporting it. Beside it is a mass connected to a spring of spring constant 61.56 N/m. What should be the mass of the object connected to the spring so that the two oscillating systems can resonate with each other?