A 8.00-cm tall object is placed 28.8 cm in front of a 18.0-cm focal length converging lens, and an image is formed 48.0 cm in back of the lens that is -13.3 cm tall. The
magnification of the image must be and the negative sign means it is

Arod of some material 0.20 m long elongates 0.20 mm on heating from 21 to 120°c. determine the value of the linear coefficient of thermal expansion [in (degrees c)^-1] for this material.

An electron and a proton are held on an x axis, with the electron at x = + 1.000 m and the proton at x = - 1.000 m. part a how much work is required to bring an additional electron from infinity to the origin? express your answer with the appropriate units. part b if, instead of the second electron coming in from infinity, it is initially at x = + 20.00 m on the axis and is given an initial velocity of 100.0 m/s toward the origin, does it reach the origin? part c how close to the origin does it come?

The texture of obsidian is best described as glassy.why does obsidian contain few or no mineral grains? by the way i put it under physics because that's what it's labeled as on my side.