Answer:
Gina should put “rubber tires” under “Synthetic.”
Gina should put “starch” under “Natural.”
Explanation: I just did the assignment ;P
Answer:
The force constant is 
The energy stored in the spring is 
Explanation:
From the question we are told that
The mass of the object is 
The period is 
The period of the spring oscillation is mathematically represented as

where k is the force constant
So making k the subject

substituting values


The energy stored in the spring is mathematically represented as

Where x is the spring displacement which is given as

substituting values


Explanation:
If the two charges are point charges - i.e., they don't have a size - the force between these charges depends on the
• Magnitude if each charge, q1 and q2
• Sign of each charge (+ or -)
• Distance between the charges, r
This is essentially Coulomb’s Law:
FE = (kq1q2)/r2
For collections of charges, you need to find the electric field E, and then use this fields to find a force on a small test charge q in the field. The test charge is always small to help you map the electric field, but not disturb it.