Final answer:
The percent uncertainty of a measuring tape that can be off by 0.50 cm over 20 m is calculated by dividing the error by the total distance and multiplying by 100, resulting in a 0.025% uncertainty.
Step-by-step explanation:
The student asked about the percent uncertainty when using a measuring tape that can be off by 0.50 cm over a distance of 20 meters. To calculate the percent uncertainty, we consider the possible error relative to the total measurement. This can be calculated by dividing the error by the total distance and then multiplying by 100 to get a percentage. So, the calculation would be (0.50 cm / 20 m) × 100. Since 20 meters is equal to 2000 centimeters, this calculation simplifies to (0.50 cm / 2000 cm) × 100, which equals 0.025%. Therefore, the percent uncertainty of the measuring tape is 0.025%.