Final answer:
To find the average acceleration of an automobile with a change in velocity from 10 mi/hr to 50 mi/hr over 3.5 seconds, division by time in the correct units is needed. A direct calculation using mi/hr and seconds leads to an unreasonably high acceleration value, indicating a missing conversion step for units. Thus, the calculation cannot be completed accurately without further information.
Step-by-step explanation:
To calculate the acceleration of an automobile that changes its velocity from 10 mi/hr to 50 mi/hr in 3.5 seconds, we can use the formula for acceleration, which is the change in velocity divided by the time over which the change occurs. The change in velocity is 50 mi/hr - 10 mi/hr, which equals 40 mi/hr. The time is 3.5 seconds. However, to find the acceleration in conventional units of mi/hr², we need to convert the time from seconds to hours (3.5 s × 1 hr/3600 s = 0.00097222 hrs). The acceleration is then (40 mi/hr) / (0.00097222 hrs) which is approximately 41160 mi/hr². Since this number is not a reasonable acceleration for an automobile and is not one of the answer choices, it's important to realize that the acceleration should be in the units of mi/hr² per second rather than per hour to make sense in this context. In other words, we keep the time in seconds and the velocity in mi/hr and calculate the acceleration as: acceleration = (40 mi/hr) / (3.5 s).
Since we do not have the conversion factor from mi/hr to mi/hr² per second in the given information, we're unable to complete the calculation precisely. However, knowing that acceleration is typically measured in units like m/s², we can infer that we're missing a step in converting mi/hr to a unit that can be divided by seconds (such as feet per second squared) for a meaningful acceleration calculation. Without that conversion factor, no precise answer can be given from choices A to D.