Answer :
Answer:
S = 30 mph
Step-by-step explanation:
A car’s speed before a sudden stop can be estimated by the formula :
[tex]S=\sqrt{30gk}[/tex]
Here,
S = speed of the car in mph,
g = drag factor, and
k = length of skid mark in feet
If drag factor is 1, k = 30 feet
So,
[tex]S=\sqrt{30\times 1\times 30}\\\\S=30\ mph[/tex]
Therefore, the correct option is (a) 30 mph.