Does anyone understand this stuff?

a local radio shack store wants to buy a new line of plasma tv's. manufacturer a offers chain discounts of 18/12, while manufacturer b offers terms of 17/13. the single equivalent discount rate of ? is the best deal.

Manufacturer A: 0.2784 or 27.84%

Manufacturer B: 0.2779 or 27.79%

Therefore, there is not much of a relevant difference but still manufacturer A has a better offer.

Explanation:

calculating the equivalent final discount rate using the formula:

FD= [1- (1-D1(%)) x (1-D2(%))]

D1: first discount to retail price (%)

D2: second discount to the first net price (%)

FD: Final equivalent discount rate (%)

observation: the expression can always be expanded to add more chain discounts using the same principles.

*Manufacturer A 18/12

Chain Discount:  D1= 18 D2= 12

FD= [1- (1- 0.18) x (1-0.12)] ≅ 0.2784

* Manufacturer B 17/13

Chain Discount: D1= 17 D2= 13

FD= [1- (1- 0.17) x (1-0.13)] ≅ 0.2779

grav forces affect all objects magnetic forces affect magnetic objects and electric currents

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.