When a mass rests on a surface, the surface "pushes up" on the object with a force that is equal in
magnitude to the gravitational force exerted by the object on the surface. this is sometimes called the
"normal force." suppose that a 30 kg basset hound rests on a couch. what is the magnitude of the normal
force that the couch exerts on the dog? hint: the acceleration due to gravity on the earth's surface is 9.8
m/s2 and 1 newton = 1 kg m/s2

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.