Preparing for Standardized Tests
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Use inverse operations to solve for s.
Substitute the given coefficient of friction and evaluate.
Substitute the given coefficient of friction and evaluate.
s=sqrt(30fd)
s≈52 miles per hour
s≈63 miles per hour
We are asked to solve the given equation for s.
LHS * 30f=RHS* 30f
sqrt(LHS)=sqrt(RHS)
sqrt(a^n)=a
Rearrange equation
To find the speed when the skid marks are 120 feet long and the coefficient of fraction is 0.75 we will use the formula we found in Part A. Let's substitute these values for d and f into s=sqrt(30fd) and evaluate.
d= 120, f= 0.75
Multiply
Use a calculator
Round to nearest integer
When the coefficient of friction for the road is 0.75, the speed of the car is about 52 miles per hour.
Again, we want to find the speed when the skid marks are 120 feet long. This time, however, the coefficient of the fraction for the road is 1.1. To do this we will use the formula we found in Part A. Let's substitute these values for d and f into s=sqrt(30fd), and evaluate.
d= 120, f= 1.1
Multiply
Use a calculator
Round to nearest integer
When the coefficient of friction for the road is 1.1, the speed of the car is about 63 miles per hour.