A car engine moves a piston with a circular cross section of 7.500±0.002 cm diameter a distance of 3.250±0.001 cm to compress the gas in the cylinder. (a) By what amount is the gas decreased in volume in cubic centimeters? (b) Find the uncertainty in this volume. [toggle] The average volume is Get the percent … Continue reading College Physics Problem 1.28

# Tag: Precision

The length and width of a rectangular room are measured to be 3.955 ±0.005 m and 3.050 ± 0.005 m . Calculate the area of the room and its uncertainty in square meters. [toggle] The average area of the room is Compute for the percent uncertainties of each dimension. The percent uncertainty in the area … Continue reading College Physics Problem 1.27

When non-metric units were used in the United Kingdom, a unit of mass called the pound-mass (lbm) was employed, where 1 lbm=0.4539 kg. (a) If there is an uncertainty of 0.0001 kg in the pound-mass unit, what is its percent uncertainty? (b) Based on that percent uncertainty, what mass in pound-mass has an uncertainty of … Continue reading College Physics Problem 1.26

The sides of a small rectangular box are measured to be 1.80±0.01 cm, 2.05±0.02 cm, and 3.1±0.1 cm long. Calculate its volume and uncertainty in cubic centimeters. [toggle] The average volume of the box is The percent uncertainty for each of the dimensions: The percent uncertainty in the volume of the box is calculated by … Continue reading College Physics Problem 1.25

A marathon runner completes a 42.188-km course in 2 h, 30 min, and 12 s. There is an uncertainty of 25 m in the distance traveled and an uncertainty of 1 s in the elapsed time. (a) Calculate the percent uncertainty in the distance. (b) Calculate the uncertainty in the elapsed time. (c) What is … Continue reading College Physics Problem 1.24

If a marathon runner averages 9.5 mi/h, how long does it take him or her to run a 26.22-mi marathon? [toggle] The relationship of the velocity (or speed), time and distance is So, by rearranging the equation, we can equate time to By direct substitution [/toggle]

What is the area of a circle 3.102 cm in diameter?

A person measures his or her heart rate by counting the number of beats in 30 s. If 40±1 beats are counted in 30±0.5 s, what is the heart rate and its uncertainty in beats per minute?

(a) A person’s blood pressure is measured to be 120±2 mmHg. What is its percent uncertainty? (b) Assuming the same percent uncertainty, what is the uncertainty in a blood pressure measurement of 80 mmHg?

(a) If your speedometer has an uncertainty of 2.0 km/h at a speed of 90 km/h, what is the percent uncertainty? (b) If it has the same percent uncertainty when it reads 60 km/ h, what is the range of speeds you could be going?