can some one help me understand this?

Question

An object of 2 g suspended from a spring stretches the spring to a length of 6 cm. An object of 5 g stretches the spring to a length of 6 cm. Let x represent grams and y represent centimeters. What is the slope of the line through the two points that describe the relationship between the number of grams and the length of the stretched spring?

A.

Option 1: 2/3

B.

Option 2: 3/5

C.

Option 3 :3/2

D.

Option 4 :5/3


Between 1970 and 1980, the Rockfort Corporation used a 10-year expansion plan to steadily increase its annual earnings. The corporation had earnings of $3.6 million in 1975 and $6 million in 1977. Create a graph and estimate the corporation's annual earnings in 1972.

A.

$0

B.

$2 million

C.

$3 million

D.

$4 million

Answer 1

#1 I believe you have a typo. Is both masses (2g & 5g) stretch the spring 6cm, then the slope of the line describing the weight / displacemnet (g/cm) is zero (0).
#2 Between 1975 &1977, the company averaged m = ($6M-$3.6M)/(1977-1975) = $1.2M / yr. Now go backwards to find earnings at 1972: Xf = Xi + m*t
Xf = $3.6M
m is found above
t = 1975 - 1972
find Xi

Answer 2

When x = 2g, distance = 6cm
When x = 5g, distance = 6 cm
Therefore slope = 0. Since this is not one of the answers, you probably have misstated the problem. One would thing 5 grams would stretch th spring farther unless the spring was extended to its maximum by the 2 grams.


The slope is (6 - 3.6)/ (1977-1975) = 1.2
So equation is y = 1.2x +b
when x = 7 (for 1977), y = 6
So 6 = 1.2(7) + b
b= - 2.4
y= 1.2x - 2.4 where x = number of years after 1970
So in 1972 we have y = 1.2(2) -2.4 = 0
The answer is A

Answer 3

the first problem is mistated. It says that the spring is 6 cm long under both weioghts, an obvious impossibility.


create a chart with years along the bottom axis and millions along the vertical axis. now plot a point at 3.6 million for 1975 and 6 million for 1977.
draw a line betwwen the pltted points and extend the line back to 1972. The corresponding millions is 0 . therefor the answer is A.

Answer 4

The questions seem pretty straightfoward. I trust you've been studying this in school. Are you trying to get someone to do your homework for you? tsk tsk..