A projectile is launched from ground level at an angle of 60.0° above horizontal with a speed of 30.0 m/s. If the projectile is moving over level ground, how long is it in the air before it again contacts the ground?

Why does lightning travel from clouds to the ground?

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?

Can someone answer my last question i posted? on my last post? my hw is due tomorrow and i’m confused.