Answer:
Mendeleev
Explanation:
He discovered the periodic table trying to organize the elements in 1869
Answer:
I've never been in a earthquake
Answer:
A)F
B)F
C)T
Explanation:
A)
This is not always true that the product of the two vector's always non-negative .It may be positive or negative.
That is why this statement is false.
B)
The unit vectors in three perpendicular direction is i ,j and k.
We know that for unit vectors
i.i=j.j=k.k= 1
i .j= j.k=k.i=0
Therefore only parallel component of the force will contribute in the integral part instead of perpendicular component of the force.
That is why this statement is false.
C)
This statement is True.
A)F
B)F
C)T
1. Answer: Option C
Displacement is a vector quantity. It has both magnitude as well as direction. Hence, it can be positive, zero or negative. In the given question, downward direction is taken as negative. This we have come to know from the downward acceleration 
. The negative sign indicates that downward direction is considered negative.
Now, since the object is dropped from the top. The displacement should be negative, because the negative represent a downward direction.
2. Answer: velocity
The truck is travelling at 30 mph to the west. From the unit mph (miles per hour), we know its a magnitude of velocity. West indicates the direction. Hence, the given quantity is a vector -velocity.
It is not speed because speed only indicates the magnitude and not the direction. speed is a scalar quantity.
Explanation:
1) Radar uses radio waves, which are a type of electromagnetic energy. Sonar uses the echo principle by sending out sound waves underwater or through the human body to locate objects. Sound waves are a type of acoustic energy. Because of the different type of energy used in radar and sonar, each has its own applications.
2)Radar systems operate using radio waves primarily in air, while sonar systems operate using sound waves primarily in water (Minkoff, 1991). Despite the difference in medium, similarities in the principles of radar and sonar can frequently result in technological convergence.
