Your car rides on springs, so it will have a natural frequency of oscillation. (Figure 1) shows data for the amplitude of motion of a car driven at different frequencies. The car is driven at 24mph over a washboard road with bumps spaced 12 feet apart; the resulting ride is quite bouncy. Determine the frequency of the oscillation, caused by the bumps. 1 mile is 5280 feet.
The graph shows a curve that extends over 6hz. It has a peak.
3 answers
A 1000-kg car traveling on a horizontal road at 24m/s sees a cow 50m ahead. Will the car be able to stop before reaching the cow? The maximum coefficient of friction between the car tires and the road is 0.60. Ignore the driver’s reaction time and assume that g=10m/s^2
First, find the frequency by unit conversions.
frequency = (24 miles/1 hour)(5280 feet/1 mile)(1 hour/3600 seconds)(1/12 feet) = 2.933 Hz
Then, read the graph to see if you need to speed up or slow down. Speeding up moves you towards 6 Hz. You want somewhere where the amplitude is low. Move just one Hz to either side when reading the graph. Don't try to make the car slow to zero.
frequency = (24 miles/1 hour)(5280 feet/1 mile)(1 hour/3600 seconds)(1/12 feet) = 2.933 Hz
Then, read the graph to see if you need to speed up or slow down. Speeding up moves you towards 6 Hz. You want somewhere where the amplitude is low. Move just one Hz to either side when reading the graph. Don't try to make the car slow to zero.
What is the frequency of a rides oscillation
6 answers