Final answer:
In a climb with a constant power setting, changes in airspeed can result from adjustments to the angle of climb or the rate of climb. This happens because the power is fixed and used to alter potential energy, which affects airspeed. Similar principles of potential and kinetic energy apply to elevators moving at a constant velocity.
Step-by-step explanation:
In a climb, with a constant power setting, any change in airspeed must be accompanied by a change in angle of climb or rate of climb since the power is being used to either increase the potential energy of the aircraft or to maintain a certain speed. Climbing relates to changes in the potential energy as the aircraft gains altitude.
When the power is constant and the aircraft climbs, the energy used for gaining altitude (potential energy) means there is less energy available for forward motion, which results in a reduction of airspeed if the climb angle or climb rate increases.
If we are discussing an elevator, an increase in height without acceleration suggests that the elevator is moving upward with a constant velocity which means that the potential energy of the elevator is increasing but kinetic energy is unchanged. This is analogous to the aircraft situation where climbing at a constant speed implies an increase in potential energy but no change in kinetic energy.
However, unlike the aircraft, the elevator does not change airspeed but rather its kinetic energy remains constant as it moves at constant velocity.
The three ways an object can accelerate are by speeding up, slowing down, or changing direction. In the context of climbing, accelerating upward would mean increasing the rate of gain of altitude, which at a constant power setting, would necessarily result in a decrease in airspeed.