If an automobile moving at a speed of 30 miles per hour can stop in a distance of 100 feet,
how much distance should it take for a car moving at 90 miles per hour to stop on the same surface?
(A) 100ft.
(B) 300ft.
(C) 400ft.
(D) 900ft.
If an automobile moving at a speed of 30 miles per hour can stop in a distance of 100 feet,
how much distance should it take for a car moving at 90 miles per hour to stop on the same surface?
(A) 100ft. --- No.
It will take more distance.
If an automobile moving at a speed of 30 miles per hour can stop in a distance of 100 feet,
how much distance should it take for a car moving at 90 miles per hour to stop on the same surface?
(B) 300ft. --- No.
It is proportional to K.E.
which is proportional to the square of the speed.
If an automobile moving at a speed of 30 miles per hour can stop in a distance of 100 feet,
how much distance should it take for a car moving at 90 miles per hour to stop on the same surface?
(C) 400ft. --- No. That would be right
if the speed were doubled.
If an automobile moving at a speed of 30 miles per hour can stop in a distance of 100 feet,
how much distance should it take for a car moving at 90 miles per hour to stop on the same surface?
(D) 900ft. --- Yes.
Speed is multiplied by a factor of 3 so K.E. is multiplied by 3 times 3.
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