A cannonball of mass 29.3 kg is shot into the air at an angle of 45 degrees with respect to horizontal. At the top of its ballistic trajectory, the cannonball suddenly explodes into two separate pieces, a smaller piece this is 1/3 the original mass, and a larger piece that is 2/3 the original mass. The smaller piece ends up landing right back at the spot where the cannonball was originally launched 29.8 seconds after it was launched. How far from the launch site does the larger piece travel? You can neglect the effects of air resistance. (Hint: you'll want to go back and review ballistic motion equations).

two charges are fixed in place on the x-axis as shown. the charge at x = 0 is negative and has magnitude q = 2 μcoulombs (1 μcoulomb = 10-6 coulombs). the charge at x = d, (d = +12 cm), is positive and has magnitude q = 4 μcoulombs. find a point x = xo along the x-axis at which the electric field is zero.

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.