Select all the correct answers. Which situations describe an elastic collision?
A. Two glass marbles bounce off each other.
B. Rodrick flops onto his sofa and sinks into the cushion.
C. A tossed water balloon flattens when it lands on the grass.
D. A bowling ball knocks over five pins.

4

explanation:

4

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.