Speed is measured in?

• A. Meters per second
• B. Millimeters per microsecond
• C. Seconds
• D. Kilometers per hour

Answer: (A)

Speed is a rate: how far something moves in a given amount of time. Because it’s distance divided by time, the units must be distance per time. In the SI system, the standard unit for speed is meters per second, which directly expresses how many meters are covered each second. Using kilometers per hour is also a valid speed unit, but it’s less convenient for precise calculations in physics. Seconds alone are a unit of time, not speed, and millimeters per microsecond is a valid but unusual speed unit that isn’t the conventional choice for typical problems. So, meters per second is the best answer.