Determine the minimum length (in ft) of a sag vertical curve if the grades are −6 percent and +3 percent. design speed is 60 mi/h. consider the following criteria—stopping sight distance, comfort, and general appearance. (assume the perception-reaction time is 2.5 seconds, deceleration rate is 11.2 ft/s2, and the sight distance is less than the length of the curve.)

Currents in dc transmission lines can be 100 a or higher. some people are concerned that the electromagnetic fields from such lines near their homes could pose health dangers. for a line that has current 150 a and a height of 8.0 m above the ground, what magnetic field does the line produce at ground level? express your answer in teslas and as a percentage of the earth’s magnetic field, which is 0.50 g. is this value cause for worry?