An object 3 cm tall is placed 20 cm from the front of a concave mirror with a radius of curvature of 30 cm. a. compute the focal distance of the focal point to the mirror. b. compute the image distance from the lens c. look at the magnification distance in problem 2, and compute the magnification of the image.

Can someone explain to me how to do this problem ?

(science)study the following ocean currents map. an ocean currents map is shown. on the map the locations for san diego, california and savannah, georgia are marked. there is a looping current from the north past san diego and a looping current from the south near savannah which statement is most likely correct about the average temperatures in san diego, california as compared to savannah, georgia? it is higher in savannah because of the cool ocean currents from the south. it is higher in savannah because of the warm ocean currents from the north. it is lower in san diego because of the warm ocean currents from the south. it is lower in san diego because of the cool ocean currents from the north.

How is coal extracted from mountaintop removal mines? a. dynamite is used to create underground tunnels where miners go to extract the coal. b. dynamite is used to break apart rocks and then draglines are used to remove the broken rock and reach the coal. c. coal in mountaintops is extracted by digging strips in the landscape to reach the coal. d. placer deposits in mountain river bottoms are removed by