Final answer:
The highest speed from which a car can stop without hitting a child is determined by calculating the sum of the reaction and braking distances, which must not exceed 45-50 feet, considering the driver's reaction time, road conditions, and vehicle characteristics.
Step-by-step explanation:
The question involves determining the highest speed at which a car can stop without hitting a child that suddenly enters the road. To calculate this, we need to consider the car's reaction time, braking distance, and the total distance needed to avoid an accident.
Assuming the driver has a reaction time of 0.5 seconds and good brakes, we begin by calculating the distance covered during the reaction time (reaction distance). Then, using the formula for stopping distance under constant acceleration, we determine the braking distance. The sum of the reaction distance and the braking distance should not exceed the distance between the car and the child (45-50 feet).
Without specific values for acceleration and the car's initial velocity, we cannot provide a numerical answer. However, we can infer from related physics problems, such as the example where a truck with good brakes stops within a certain distance, that such calculations typically involve physics equations of motion. For a more definitive answer, one would perform the necessary calculations with the relevant coefficients of friction, vehicle speed, and road conditions.