If a ball is tossed straight up into the air, at what position is its potential energy the greatest?
a. when it reaches the top of its flight
b. when it first leaves your hand
c. when it approaches the top of its flight
d. when it begins to fall back to your hand.

.

A.when it reaches the top of its flight

Explanation:

The potential energy of an object is given by:

where

m is the mass of the object

g is the acceleration of gravity

h is the heigth at which the object is located above the ground

Therefore, we see that the higher the object, the larger its potential energy: this means that the ball will have the greatest potential energy at the top of its trajectory.

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.