By putting an apple up on high ground. (That is 1 example)
This creates a higher gravitational force, and when it falls down it would have a lot of kinetic energy. But, if put on low ground, it wouldn't have enough potential energy to increase the kinetic energy.
That information describes the plane's speed.
If he had also told them what direction they were flying, then
they would have been able to put the two pieces of information
together, and they would know the plane's velocity.
A cascade effect is an inevitable and sometimes unforeseen chain of events due to an act affecting a system. If there is a possibility that the cascade effect will have a negative impact on the system, it is possible to analyze the effects with a consequence / impact analysis. An example of the cascade effect caused by the loss of a top predator is apparent in tropical forests. When hunters cause local extinctions of top predators, the predators' prey's population numbers increase, causing an overexploitation of a food resource and a cascade effect of species loss. Another example is a lake system with four trophic levels, the model predicts with the removal of the top carnivore, the primary carnivore numbers will increase, in turn, reducing the number of herbivores, increasing the phytoplankton abundance, and decreasing the levels of mineral nutrients. The effects show a positive/ negative change in trophic level structure as it moves down.
Answer:
0.544 eV
Explanation:
To ionize the hydrogen atom 
So the required energy is
as
So 
We have to calculate the energy required to ionize hydrogen atom when it is in n=5
So the energy should be less than 