Two cars are travelling around identical circular racetracks. Car A travels at a constant speed of 20 m/s. Car B starts at rest and speeds up with constant tangential acceleration until its speed is 40 m/s. When car B has the same (tangential) velocity as car A, it is always true that:
A)it is passing car A.
B)it has the same linear (tangential) acceleration as car A.
C)it has the same centripetal acceleration as car A.
D)it has the same total acceleration as car A.
E)it has travelled farther than car A since starting.

Question

Quizplus · Accepted Answer

Both cars are travelling on identical circular racetracks, so they have the same radius and therefore the same centripetal acceleration. The tangential acceleration of car B is not given to be equal to that of car A, so choice B is not necessarily true. Choices A and E are also not necessarily true based on the given information. Choice D is ambiguous because it is not specified whether "total acceleration" refers to the vector sum of tangential and centripetal acceleration or simply the magnitude of the tangential acceleration. Therefore, the correct choice is C, as both cars have the same centripetal acceleration.

Two Cars Are Travelling Around Identical Circular Racetracks