# Worksheet: Combining Uncertainties

In this worksheet, we will practice finding the uncertainties in the values of quantities that can be calculated from two or more measured values.

Q1:

A wire carries a current of for a time of . What is the percent uncertainty of the charge that passes through the wire in that time?

• A5%
• B0.0625%
• C60%
• D6.25%
• E0.6%

Q2:

Three objects have masses of , , and . What is the uncertainty in the total mass of the three objects?

Q3:

Cupronickel is an alloy made of copper and nickel. If of cupronickel contains of copper, what is the uncertainty in the amount of nickel it contains?

Q4:

An iron block has a mass of . The acceleration due to gravity is . What is the uncertainty in the weight of the block?

Q5:

An object has a mass of and is moving at a speed of . What is the uncertainty in the kinetic energy of the object? Start by calculating the uncertainty in , and then calculate the uncertainty in .

Q6:

A force of is applied to an object with a mass of . What is the uncertainty in the acceleration of the object?

• A2 m/s2
• B0.4 m/s2
• C40 m/s2
• D0.2 m/s2
• E0.02 m/s2

Q7:

Two resistors that are in series in a circuit have a combined resistance of . One of the resistors, with a resistance of , is removed. What is the uncertainty in the resistance of the remaining resistor?

Q8:

A resistor in a circuit has a resistance of . The current through the resistor is . Work out the potential difference across the resistor as well as the percent uncertainty in this value.

• A
• B
• C
• D
• E

Q9:

In an experiment, a quantity is found to have a value of . What is the uncertainty in ?

Q10:

A scientist must mix the correct volumes of two liquids, liquid A and liquid B, as part of an experiment. He must mix 500 mL of liquid A with 200 mL of liquid B. He uses a measuring cylinder to measure the volume of each liquid first. The measuring cylinder has a resolution of 5 mL. He then mixes the two liquids. What is the uncertainty in the volume of the mixture?

Q11:

In an experiment, a quantity is found to have a value of . What is the percent uncertainty in ?

• A0.09%
• B0.6%
• C4%
• D2%
• E9%

Q12:

Two resistors have resistances of and . If the two resistors were placed in series, what would the uncertainty of the two resistors together be?

Q13:

An object moves along a straight line at a speed of for . Work out the distance that the object moves as well as the uncertainty in this value.

• A
• B
• C
• D
• E

Q14:

A sound wave travels through a medium with a speed of . The wavelength of the sound wave is . What is the percent uncertainty in the frequency of the sound wave?

• A
• B
• C
• D
• E