Answer:
stopwatch
Explanation:
A stopwatch is a special hand held device which is used to measure time especially in races. It is mounted with a timer that has start, stop and pause buttons to calculate the time taken its activation and deactivation. It can measure the time taken fro the starting zero position to the final position. Thus, stopwatch can be used to measure the time taken for a toy car to go down a ramp.
Thus, answer is stopwatch.
