An eighth-grade class is studying the motion of objects. They have learned the following concepts about motion. Motion occurs when there is a change in the position of an object with respect to a reference point.
While the speed of the object may change at various times during a trip the average speed for the trip is found by dividing the total distance by the total time.
The motion of the object can be changed by varying the amount of net force acting on the object or by varying the mass of the object.
The teacher asked students to design investigations to determine how changing the forces acting on an object or the mass of the object would change its motion.
The materials for the investigation included:
1 - toy cart
3 - 10N weights
1 - pulley
2 - meters of string
One group of students decided to design an investigation to determine how different amounts of mass on the toy cart would affect the speed of the toy cart. They set up their investigation as shown below:

The students performed several trials using different masses in the toy cart (M1). They hung a mass shown as (M2) to pull the toy cart as it dropped.
Below is a table they made to record their results.

Which of the following would be a way to test the effect changing the amount of force acting on the object has on the average speed of the object?

elly's long hair:

a. if the salon only takes cash, then this isn't the problem. it doesn't matter how much she has in her checking account.   she can't get a haircut until she has the cash.

b. if she has overdraft protection, then there's no problem.   she can go ahead and write a check that her account can't cover, then sometime later, pay the bank some outrageous usury for loaning her a few bucks for a few days, but with beautiful hair.

c. if elly has some principles, and doesn't want to write a bad check, then now she has a problem.   her desire for the new hairstyle is in conflict with her honesty and integrity.

d.   if the bank will not process a check she writes, then even if she had a million $$ in her account, she couldn't use any of it.   the amount she has in her account is not the problem.   and if i may suggest, she might as well close her checking account, and put the money where it'll work for her.   it's not doing her a bit of good in a checking account, since she can't write any checks.

justin can't pay the full balance:

a. he can't even handle the credit limit he has now.   under no circumstances should he ask for a higher limit.

b.   he can ask for the grace period to be extended.   but that's no solution, the bank will almost certainly refuse anyway, and there are much better options.   he knew the rules of his credit card when he started using it.

c.   he definitely should pay the interest on the balance, plus as much of the balance as he can cover at the same time.

d.   he definitely should pay the minimum otherwise they could shut down his card.   he should also pay as much more as he possibly can.   he should also remember the awkward situation he's in, stop buying stuff on credit that he can't afford, and avoid adding any more debt.

i'd say that justin's best best option isn't on this list of choices.   what he has to do:   pay as much as he can at least the minimum payment plus as much more as he can and then avoid adding more debt.