A circus diver drops from a high pole into water far below. When he is halfway down A circus diver drops from a high pole into water far below. When he is halfway down his kinetic energy and potential energy are equal. his potential energy is halved. he has gained an amount of kinetic energy equal to half his initial potential energy. all of the above none of the above

Consider an object launched vertically upward with an initial speed v. Neglect air resistance.

1. As the projectile goes upward, what energy changes take place?
   • Both kinetic and potential energy decrease.
   • Both kinetic and potential energy increase.
   • Kinetic energy decreases; potential energy increases.
   • Kinetic energy increases; potential energy decreases.
2. At the top point of the flight, what can be said about the projectile's kinetic and potential energy?
   • Both kinetic and potential energy are at their maximum values.
   • Both kinetic and potential energy are at their minimum values.
   • Kinetic energy is at a maximum; potential energy is at a minimum.
   • Kinetic energy is at a minimum; potential energy is at a maximum.

A roller coaster starts from rest at point A.

If you ignore friction and take the zero of potential energy to be at C,

(a) the kinetic energy of the coaster at D will be equal to its potential energy at A.

(b) the kinetic energy of the coaster at E will be equal to its potential energy at C.

(c) the kinetic energy of the coaster at C will be equal to its potential energy at A.

(d) the kinetic energy of the coaster at B will be equal to its potential energy at C.

(e) the kinetic energy of the coaster at C will be equal to its potential energy at B.