does anyone know how to do this? T. Section 6.8 Use the four-step procedure for

Question

does anyone know how to do this?

T. Section 6.8 Use the four-step procedure for solving variation problems given below to solve the exercise 5. Write an equation that models the given English statement. 6. Substitute the given pair of values into the equation in step 1 and find the value of k, the constant of variation. 7. Substitute the value of k into the equation in step 1. 8. Use the equation from step 3 to answer the problem's question. On a dry asphalt road, a car's stopping distance varies directly as the square of its speed A car traveling at 45 miles per hour can stop in 67.5 feet. What is the stopping distance for a car traveling at 60 miles per hour?

Explanation / Answer

The stopping distance (d) is directly porportional to the square root of the speed (s)
d is proportional to s2
Step 5: d= k s2 where 'k' is the constant of proportionality;  

Step 6: when s= 45 mph, d= 67.5 ft
substituting the values we get
67.5 ft = k * 452 mph
k = 67.5/452= 1.5/45 ft hr2 / mile2
Thus, the constant of proportionality k = 1.5/45 ft hr2/mile2

Step 7: d= k s2
d= 1.5/45 s1/2

Step 8: When s= 60 miles per hour, we are to find out d
d = 1.5/45 ft hr2/mile2 * 60*60 miles2/ hr2 = 120 ft mile2 hr2/ mile2 hr2 = 120 feet;

Thus, the stopping distance for a car travelling at 60 miles per hour will be = 120 feet;

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