Disturbed by speeding cars outside his workplace, Nobel laureate Arthur Holly Co
ID: 1874324 • Letter: D
Question
Disturbed by speeding cars outside his workplace, Nobel laureate Arthur Holly Compton designed a speed bump (called the "Holly hump") and had it installed. Suppose a 1 800-kg car passes over a hump in a roadway that follows the arc of a circle of radius 18.4 m as in the figure below.
(a) If the car travels at 34.0 km/h what force does the road exert on the car as the car passes the highest point of the hump? (magnitude N direction)
(b) What is the maximum speed the car can have without losing contact with the road as it passes this highest point? (km/h)
Explanation / Answer
a) 34.0 km/hr = 9.44 m/s
m g - N = [m v2/ r]
N = mg - [m v2/ r]
= (1800 * 9.8) - (1800 * 9.442 / 18.4)
force = 8922 N
b) m g - 0 = [m v2/ r]
m g = [m v2/ r]
v = sqrt (g r) = sqrt (9.8 * 18.4)
= 13.43 m/s = 48.35 km/hr