A car moves in a circular path at 15 mph. Which of the following statements about the cars motion would be correct?
a. The cars acceleration is constant.
b. The cars velocity is constant.
c. The cars speed is constant.
d. The cars velocity and speed are constant.
To determine which statement about the car's motion is correct, let's break down the given information.
We are told that the car moves in a circular path at 15 mph.
a. The car's acceleration is constant:
Acceleration is the rate at which velocity changes. In this case, because the car is moving in a circular path, its velocity is constantly changing direction, which means it has an acceleration. Therefore, option a is incorrect.
b. The car's velocity is constant:
Velocity is a vector quantity that indicates both the speed and direction of an object. Since the car is moving in a circular path, its direction is constantly changing. Therefore, the car's velocity is not constant. Thus, option b is incorrect.
c. The car's speed is constant:
Speed is a scalar quantity that indicates the magnitude of an object's velocity without considering its direction. If the car is moving at a constant 15 mph, its speed remains constant as long as it maintains that velocity. Since the question does not mention any changes in speed, option c can be considered correct.
d. The car's velocity and speed are constant:
Since we already established that the car's velocity is not constant due to its changing direction in a circular path, option d is incorrect.
Therefore, the correct statement is that the car's speed is constant (option c).