In physics, gravity is the natural force that causes things to fall toward the earth. The noun gravity can also mean seriousness or solemnity. Someone who conducts themselves with an air of gravity is someone who takes what they are doing seriously.
Answer:wave travel
Explanation:Because gravity pulls the water in the crest downward .Forced out from beneath the falling crests ,the falling water pushes former troughs upwards and the wave moves to a new position causing a disturbance.
Answer:571.09 kJ
Explanation:
Given
Temperature of cooling water from engine exit
After Passing through the radiator its temperature decreases to 
specific heat of water
Volume of water 
density of water 
Thus mass of water
Heat transferred to the surrounding is equal to heat absorbed by cooling water
A discovery not the others
Expensive: Hydrogen gas actually takes a considerable measure of work to free if from different components. If it were basic and simple to separate, everybody would be utilizing it. It’s now being utilized to power some hybrid vehicles, yet right now it is not a reasonable type of fuel for everybody, mainly because it’s pricey and it’s difficult to get it from place to place. Until research and innovation goes far enough to make this a simpler and cheaper task, hydrogen will likely be something that only the rich can afford.Not Enough Hydrogen Fuel Stations: As you likely know, it’s very difficult to change “the way things are.” As difficult as hydrogen is to create and transport, it gets to be considerably pricier when you consider attempting to utilize it to supplant fuel. There is no current framework set up to hydrogen as the primary fuel for the normal driver. Service stations and vehicles themselves would all must be changed in order to use hydrogen, which can take a lot of time and money to do. It doesn’t seem cost efficient to change from the norm.Safety Concerns: Hydrogen in itself has a lot of power behind it. Though it is less dangerous than gasoline, it’s profoundly flammable and constantly in the news for the potential dangers connected with it. Unlike gas, hydrogen has no smell. Sensors must be used to detect a leak.
