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:
Definimos:
Rapidez media es igual al cociente entre la distancia recorrida y el tiempo que se tarda en recorrer esa distancia.
En este caso la distancia recorrida es 400m, y el tiempo que se tarda es 30s, entonces la rapidez media va a ser:
RM = 400m/30s = 13.33 m/s
La velocidad media por otro lado, es igual al cociente entre el desplazamiento y el tiempo necesario para desplazarse.
El desplazamiento es igual a la distancia entre la posición final y la posición inicial, que en este caso eso 40m, y el tiempo necesario sigue siendo 30s, entonces la velocidad media va a ser:
VM = 40m/30s = 1.33 m/s
Solution :
Given data is :
Density of the milk in the tank, 
Length of the tank, x = 9 m
Height of the tank, z = 3 m
Acceleration of the tank, 
Therefore, the pressure difference between the two points is given by :
Since the tank is completely filled with milk, the vertical acceleration is 
Therefore substituting, we get
Therefore the maximum pressure difference in the tank is Δp = 47.87 kPa and is located at the bottom of the tank.
It is 2.) Cut the DNA into fragments
Answer:
because some waste heat is always produced produced in a heat engine.
Explanation:
the fraction of heat input that is converted to a net work output is a measure of the performance of the heat engine and is called the thermal efficiency.Since the machine does not contain a source of energy ,nor can it store energy ,from this conversation of energy the power output of machine can never be greater than its input,so efficiency can be less than 100%.
