Isobar line (isoline) of constant (equal) pressure. **difference = 1020 1000 = 20 mbar. **distance: 45 - 25 = 10 x 69 miles/ = 690 miles. ***gradient: 20 mbar/690 miles = . 03 mbar/mile, steep! When lines are closer together, steeper pressure gradient, winds are faster ex. at the top of a hill there is high pressure, at the bottom there is low pressure. *on non-rotating earth, winds are perpendicular to isobars. *coriolis force is an apparent force, the result of the earth"s rotation ex. Merry-go-round and ball from above, it looks like the ball travels straight but if you"re viewing from the disc, it look likes the ball is curving. Curve to the right in n. hemisphere. Curve to the left in s. hemisphere. Stationary at poles but spinning coriolis force is max. Forward 1041 mph at equator, little effective spin. *this is important for ballistics ineffective in traveling to a spot on the same latitudinal line.