Answer:
20 J
Explanation:
Given:
Weight of the book is, 
Height or displacement of the book is, 
The work done on the book to raise it to a height of 2 m on a shelf is against gravity. The gravitational force acting on the book is equal to its weight. Now, in order to raise it, an equal amount of force must be applied in the opposite direction.
So, the force applied by me should be equal to weight of the body and in the upward direction. The displacement is also in the upward direction.
Now, work done by the applied force is equal to the product of force applied and displacement of book in the direction of the applied force.
Therefore, work done is given as:

Therefore, the work done to raise a book to a height 2 m from the floor is 20 J.
Answer:
B. parents
Explanation:
one of the conclusions from Einsteins relativity theory for his equation E=
(where E is energy, m is mass and C is the speed of light),
is that time moves relative to the observer. Time moves more slowly when the observer is in motion (time dilation), therefore an individual in motion ages more slowly than someone at rest. This in fact happened when astronaut Scot Kelly spent nearly a year on board the international space station and on his return, his twin brother had aged slightly faster than him. In conclusion, if a space trip finds a son or daughter is biologically older than his or her parents, the space trip was taken by the parents.
Okay, hun. Velocity is a vector quantity that measures displacement over a period of time. Velocity = Speed/Time (v=s/t). Hope this helped you. I took physics over 4 years ago. I'm more of a biology/chemistry person. (I major in those)
Answer:
The answer
Explanation:
Thinking together, Better friendship, Makes teacher happy.