WHY DOES EVERY IMAGE DOES NOT MAKE ON FOCUS ALWAYS we all know that light from a point go to different direction so there is possibility that few light will also travel parallel to each other and fall on concave mirror .from different point few light will travel also parallel, so why does not every image not made on focus in concave mirror

A26 cm object is 18 cm in front of a plane mirror. a ray of light strikes the object and is reflected off the mirror at a 42-degree angle. what is the angle of reflection? degrees what type of image is formed? what is the size of the image? cm

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.

Looking at this barometer, is the air pressure high or low? what type of weather would you expect? high, bad low, bad high, good low, good