Answer:
Because when people under the age of 21 try to buy alcohol, they need to be verified by their state that they are that age. So if they are under legal age, 21, the store isn't allowed to give them the Alcoholic beverage.
Explanation:
The average adult in the us spends 24 hours watching televistion each week
Answer:
Mechanical energy is the energy that is possessed by an object due to its motion or due to its position. Mechanical energy can be either kinetic energy (energy of motion) or potential energy
When the child is moving, he/she has kinetic energy. For just a brief second before they move the other way, the child is not moving, but they have gravitational potential energy.
The child may need a push from time to time because friction with the air causes loss of energy.
Answer:
Same direction: t=234s; d=6.175Km
Opposite direction: t=27.53s; d=0.73Km
Explanation:
If the automobile and the train are traveling in the same direction, then the automobile speed relative to the train will be 
(<em>the train must see the car advancing at a lower speed</em>), where 
is the speed of the automobile and 
the speed of the train.
So we have 
.
So the train (<em>anyone in fact</em>) will watch the automobile trying to cover the lenght of the train L at that relative speed. The time required to do this will be:
And in that time the car would have traveled (<em>relative to the ground</em>):
If they are traveling in opposite directions, <u>we have to do all the same</u> but using 
(<em>the train must see the car advancing at a faster speed</em>), so repeating the process:
