Mechanics Kinematics I: Speed in one dimension by Thomas Pasquini, Ph.D. Reading Quiz Teach with this The definition of average speed of an object is ________. the position of an object divided by what time it is the amount of time required to travel 1 meter the amount of distance traveled in 1 hour the ratio of the distance traveled to the time elapsed Which of the following quantities is not a measurement of speed, based on the units being used? 25 m2 60 km/h 2.3 mm/s 150 miles per day On a trip in your car, you pass mile marker 75 at 1:00 PM. At 4:00 PM, you pass mile marker 240. What is your average speed during this part of the trip? 55 mph 75 mph 80 mph 60 mph Which statement about the relationship between velocity and speed is true? The units of velocity are always m/s. Speed has units of miles per hour. Velocity describes both the speed and the direction of motion. Velocity and speed are just different words for the same quantity. Speed describes motion that is constant. Velocity describes an object that is speeding up or slowing down. What is the main reason that Galileo's experiment to measure the speed of light could not measure the speed of light? Galileo used geometry, not algebra. He had no way to use his measurements to calculate speed. Galileo's did not have the ability to measure extremely short times. Light travels instantaneously, so there is no such thing as a speed of light. Galileo was not able to see the lantern light from so far away and needed to move closer. Which statement accurately relates two representations of an object's constant speed motion? The slope of a position vs time graph is the same as the value of object's speed. The difference between the starting and ending position from a table of values is the same as the object's speed. The y-intercept of the graph of position vs time will be the same as the speed of the object. The speed can be found at each moment by dividing the position in the table by the time the position was measured. For the motion described by the equation above, what is the speed of the object? Assume that position is measured in meters and time in seconds. 0.25 m/s 4 m/s 5 m/s 20 m/s Which experimental setup would allow a scientist to make an accurate measurement of a speed that is very small (slow)? The experiment makes precise measurements of small changes in position as it changes over long periods of time. The experiment makes measurements of small changes in position and precise mesurements of small amounts of time. The experiment makes measurements of large distances traveled and precise measurements of short times. The experiment measures the amount of force that is needed to stop the object from moving. Which value is approximately the same as 100 km/h? 0.028 m/s 28 m/s 100 mph 100,000 m/s Which statement about the speed of light is true? The speed of light is about the same as the speed of sound. Light travels at the same speed through air, glass, and water. The speed of light remains an unanswered question. Scientists are working to develop experiments that will measure the speed accurately. The scientific community has defined the speed of light as a fundamental constant. Score Quiz