A1.50-kilogram ball is attached to the end of a 0.520-meter string and swung in a circle. the velocity of the ball is 9.78 m/s. what is the tension in the string? 74.6 n 276 n 28.2 n 3.39 n

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?