Calculate the wavelengths of a 1.95-GHz cell phone signal.

A. 0.153 m
B. 1.53*10^8 m

moving ball hits still ball. mover stops, hit ball moves. momentum transfer.

e/c, where e is its total energy

there are no contact forces mentioned on the list of choices that you've provided.

the answer is the first electromagnet (a). this is because it has more coils around the ferromagnetic material. increasing the number of coils increases the surface area in which the metal interacts with the current in the coil. this enables more atoms in the metal to become aligned hence becoming more magnetized.