Which of these steps could be used in an investigation about the effect of gravity?
A.
counting how many paper clips stick to a magnet in a chain
B.
measuring the time it takes for a ball to fall a certain distance
C.
measuring the distance a toy car moves after it is pushed
D.
testing which surface is easier to slide a wooden block across

The magnitude of the magnetic field at a certain distance from a long, straight conductor is represented by b. what is the magnitude of the magnetic field at twice the distance from the conductor? a. at twice the distance, the magnitude of the field is 4b.b. at twice the distance, the magnitude of the field is 2b.c. at twice the distance, the magnitude of the field is b/2.d. at twice the distance, the magnitude of the field is b/4.e. at twice the distance, the magnitude of the field remains equal to b.