+73 The distance d (in feet) that it takes a car to come to a complete stop on dry asphalt can be modeled by d = 0.05s^2 + 1.1s where s is the speed of the car (in miles per hour). A car has 78 feet to come to a complete stop. Find the maximum speed at which the car can travel.
+654 We can already plug in 78 for d in this equation.
78 = 0.05s^2 + 1.1s
After subtracting 78 from both sides, we have:
0.05s^2 + 1.1s - 78 = 0.
Solving this quadratic, we have: s = 30.0000000000000004, -52.00000000000001
The last time I checked, we can’t go negative speed, so s = 30
It is actually 30.000000000000004, but just round it down.
+654 We can already plug in 78 for d in this equation.
78 = 0.05s^2 + 1.1s
After subtracting 78 from both sides, we have:
0.05s^2 + 1.1s - 78 = 0.
Solving this quadratic, we have: s = 30.0000000000000004, -52.00000000000001
The last time I checked, we can’t go negative speed, so s = 30
It is actually 30.000000000000004, but just round it down.
