Calculate the following, and round to the correct number of significant figures: a. (3.1 10^2 cm)x(1.22 10^4 cm)
b. (2.99x10^5km)x(6.88x10^2km)
c. (5.75x10^-5m)/(9.9x10^-2m)
d. (7.83x10^4m)/(3s)

The place you get your hair cut has two nearly parallel mirrors 6.00 m apart. as you sit in the chair, your head is 2.00 m from the nearer mirror. looking toward this mirror, you first see your face and then, farther away, the back of your head. (the mirrors need to be slightly nonparallel for you to be able to see the back of your head, but you can treat them as parallel in this problem.) how far away does the back of your head appear to be?

Clothes dryer uses about 7 amps of current from a 240 volt line. how much power does it use?

Engineers find a new metal that is stronger than steel but much lighter. this material is also significantly cheaper than what is currently used for most aircraft, available in large quantities, and easy to manufacture. the engineers are excited because this new material will lower the costs of buying and operating airplanes for companies. what is probably the best step for the engineers to make next?