A student creates the wave shown below by moving their hand up and down 5 times in 10 second. This makes 3 wave cycles in 9m.
9 m
What is the wavespeed? Input your numerical answer, without units.

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?