I'm pretty sure the answer is d.The weight of the book and the table's upward force on the book are equal in magnitude but opposite in direction.
Solution :
Acceleration due to gravity of the earth, g 

Acceleration due to gravity at 1000 km depths is :




= 8.23 m/s
Acceleration due to gravity at 2000 km depths is :




= 6.73 m/s
Acceleration due to gravity at 3000 km depths is :



= 5.18 m/s
Acceleration due to gravity at 4000 km depths is :




= 3.64 m/s
Answer:
B. Observation
Explanation:
Using a thermometer to read the temperature of a solution is tantamount to the making an observation.
Observation are recorded using our senses of sight, taste, earing, feeling etc or by the use of instrument.
- Through observation, data is usually collected to make inferences about an experiment.
- An observation leads to the formulation of a hypothesis which is scientific guess that leads to experimental designs.
- Conclusions are drawn from the information of data obtained from an experiment.
Answer:
C. 5.6 × 10^11 N/C
Explanation:
The electric field
at a distance
from a charge
is given by

where
is the coulomb's constant.
Now, in our case

;
therefore,


which is choice C from the options given<em> (at least it resembles it).</em>