Episode 2: Uncertainty and Error

What best describes the collection of data points shown on the target, where the bulls-eye represents the desired results.

• Accurate and Precise

• Precise but not Accurate

• Accurate but not Precise

• Not Precise or Accurate

A student measures the length of their desk with a meterstick multiple times. They get 1.21 m, 1.215 m, 1.22 m, 1.205 m. Which best describes this range of results?

• systematic error

• random error

• low accuracy measurements

• low precision measurements

While measuring the time it takes a toy car to travel a meter a student starts her watch when back of the car passes the starting line and stops the watch when the front of the car meets the finish line. She records 2.1s, 2.2s, 2.05s, 2.15s. What is the largest source of error in this experiment?

• Systematic Error

• Random Error

• Human Error

• The Toy Car

A student is calculating the acceleration of a falling object. She records a distance of 20.56m and a time of 2.05s. She calculates the acceleration to be 9.784651  $\frac{m}{s^2}$  . What value should she record using the proper significant figures?

• 9.8  $\frac{m}{s^2}$  

• 9.78  $\frac{m}{s^2}$  

• 9.785 $\frac{m}{s^2}$  

• 9.784651 $\frac{m}{s^2}$  

A student measures the acceleration due to gravity to be 10.0  $\frac{m}{s^2}$ . The accepted value is 9.81  $\frac{m}{s^2}$ . What is the percent error?

• 1.90%

• 1.94%

• 0.019%

• 2.02%