Answer:
, assuming that the gravitational field strength is 
.
Explanation:
Notice that both the speed and the direction of motion of this block are constant. In other words, the velocity of this block is constant.
By Newton's Second Law, the net force on this block would be 
. External forces on this block should be balanced. Thus, the magnitude of the (downward) weight of this block should be equal to the magnitude of the (upward) force that the boy applies on this block.
Let 
denote the mass of this block. It is given that 
. The weight of this block would be:
.
Hence, the force that the boy applies on this block would be upward with a magnitude of 
.
The mechanical work that a force did is equal to the product of:
- the magnitude of the force, and
- the displacement of the object in the direction of the force.
The displacement of this block (upward by 
) is in the same direction as the (upward) force that this boy had applied. Thus, the work that this boy had done would be the product of:
- the magnitude of the force that this boy exerted, , and
- the displacement of this block in the direction, .
.
High school???
No way
It's work.
Answer:
The correct option is;
B. Throughout all of history
Explanation:
A body of knowledge comprises of a given collection of concepts, activities and terms that represents a professional discipline that is outlined by the associated scholarly society, therefore, scientific knowledge, being comprised of very diverse field of knowledge, with different approaches and changing understanding is taking as a process of learning about the universe data collection, experimenting analysis and communication with a theme of systems, equilibrium, models and constant change which makes the basis of the body of scientific knowledge to be throughout all of history.
