A curve ball is a type of pitch in which the baseball spins on its axis as it heads for home plate. If a curve ball is thrown at 33.1 m/sm/s (74.0 mphmph) with a spin rate of 35 rev/srev/s, how many revolutions does it complete before reaching home plate

19.35 revolutions.

Explanation:

Let the home plate is 18.3 m (60 ft) from the pitching mound and that the baseball travels at a constant velocity.

Given that,

Velocity of ball = v = 34.5 m/s

Spin rate of ball = 26 revolutions/s

Distance between home plate and pitching mound = s = 18.3 m

We need to find the number of revolutions it complete before reaching home plate. It can be calculated as follows:

So, there are approx 19.35 revolutions.

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.