How do you know the speed of an electromagnetic wave in a vacuum?

The slope of a velocity time graph over any interval of time gives the during that interval

Two 1.20-m nonconducting wires meet at a right angle. one segment carries + 2.50 µc of charge distributed uniformly along its length, and the other carries - 2.50 µc distributed uniformly along it, as shown in fig. 21.50. ( a. find the magnitude and direction of the electric field these wires produce at point p, which is 60.0 cm from each wire. ( b. if an electron is released at p, what are the magnitude and direction of the net force that these wires exert on it?

Which one of the following terms is used to indicate the natural tendency of an object to remain at rest or in motion at a constant speed along a straight line? velocity acceleration equilibrium force inertia