Which elements could be used to make a magnet?

iron nickel and cobalt

Explanation: hope this helped

Materials that can be polarized, which are likewise the ones that are emphatically pulled in to a magnet, are called ferromagnetic (or ferromagnetic). These incorporate the components iron, nickel, and cobalt, and their amalgams, some combinations of uncommon earth metals, and some normally happening minerals, for example, lodestone.

true tan speed = ang vel x radius

can be answered using momentum.

momentum = p

p1= mass1 * velocity1

p1 = p2

therefore

p1 = 6kg * 4m/s

p1 = 24kgm/s

p2=m2 * v2

24 kgm/s = 7kg * v2

v2 = 24 kgm/s / 7kg

v2= 3.42 m/s