What is a derived unit ?

A derived unit is one that is made up of combinations of SI units.

What is the SI base unit for mass ?

The SI base unit for mass is kilograms (kg).

True or False? The SI base units for the newton are kg m s –1 .

False. The SI base unit for the newton is kg m s –2 .

What is the SI base unit for length ?

The SI base unit for length is metres (m).

True or False? The SI base unit for the joule is kg m s –2 .

False. The SI base unit for the joule is kg m 2 s –2 .

What is the SI base unit for time ?

The SI base unit for time is seconds (s).

True or False? The SI base units for the watt are kg m s –3 .

True. The SI base unit for the watt is kg m s –3 .

What is the SI base unit for current ?

The SI base unit for current is amperes , or amps (A).

True or False? The SI base unit for the pascal is kg m –1 s –2 .

True. The SI base units for the pascal are kg m –1 s –2 .

What is the SI base unit for temperature ?

The SI base unit for temperature is the kelvin (K).

True or False? The SI base unit for frequency is hertz (Hz).

False. The unit for frequency is hertz (Hz), but the SI base unit is s –1 .

What is the SI base unit for the amount of a substance?

The SI base unit for the amount of a substance is the mole (mol).

True or False? All digits of an integer number are significant if the last digit is non-zero.

True. All digits of an integer number are significant if the last digit is non-zero. For example, 702 has 3 significant figures

True or False? Zeros at the end of an integer number are always significant.

False. Zeros at the end of an integer number are never significant. For example, 306 000 has 3 significant figures

True or False? Zeros in front of an integer number are never significant.

True. Zeros in front of an integer number are never significant. For example, 0.025 has 2 significant figures

True or False? Zeros at the end of a number less than one are never significant.

False. Zeros at the end of a number less than one are always significant. For example, 0.02000 has 4 significant figures

True or False? Zeros after an integer number that has a decimal point are always significant.

True. Zeros after an integer number that has a decimal point are always significant. For example, 40.0 has 3 significant figures

What is dimensional analysis ?

Dimensional analysis is a method used to check the homogeneity of physical equations by studying the units.

Define the term resolution of a measuring instrument.

The resolution of a measuring instrument is the smallest change in the physical quantity being measured that results in a change in the reading given by the measuring instrument.

What steps need to be taken for an experiment to be valid.

For an experiment to be valid , any variable that may affect the results needs to be controlled for.

Why is it important to calibrate measuring equipment prior to taking any readings?

It is important to calibrate measuring equipment prior to taking any readings to make sure the values given by the measuring device are accurate .

What is an independent variable ?

An independent variable is a variable that is changed on purpose in order to observe the effects of the change.

What is a dependent variable ?

A dependent variable is a variable that changes in response to changing the independent variable. The effects of this change are predicted, observed, and measured.

What is a control variable ?

A control variable is any other factor that may affect the results of the investigation and must therefore be controlled for as far as possible.

A student is measuring the terminal velocity of a ball bearing in different fluids. State the following variables for this investigation: independent variable dependent variable control variables

For a student measuring the terminal velocity of a ball bearing in different fluids, the variables are as follows: independent variable - terminal velocity of ball bearing dependent variable - type of fluid control variables - height of free fall, diameter and mass of ball bearing

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FrontFundamental & Derived Units in IB Physics
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What is a derived unit?
A derived unit is one that is made up of combinations of SI units.
What is the SI base unit for mass?
The SI base unit for mass is kilograms (kg).
True or False?
The SI base units for the newton are kg m s^–1.
False.
The SI base unit for the newton is kg m s^–2.
What is the SI base unit for length?
The SI base unit for length is metres (m).
True or False?
The SI base unit for the joule is kg m s^–2.
False.
The SI base unit for the joule is kg m² s^–2.
What is the SI base unit for time?
The SI base unit for time is seconds (s).
True or False?
The SI base units for the watt are kg m s^–3.
True.
The SI base unit for the watt is kg m s^–3.
What is the SI base unit for current?
The SI base unit for current is amperes, or amps (A).
True or False?
The SI base unit for the pascal is kg m^–1 s^–2.
True.
The SI base units for the pascal are kg m^–1 s^–2.
What is the SI base unit for temperature?
The SI base unit for temperature is the kelvin (K).
True or False?
The SI base unit for frequency is hertz (Hz).
False.
The unit for frequency is hertz (Hz), but the SI base unit is s^–1.
What is the SI base unit for the amount of a substance?
The SI base unit for the amount of a substance is the mole (mol).
What is the order of magnitude of $6.32 \times 10^{8}$ ?
The order of magnitude of $6.32 \times 10^{8}$ is: $10^{9}$
What is the order of magnitude of $1.60 \times 10^{- 19}$ ?
The order of magnitude of $1.60 \times 10^{- 19}$ is: $10^{- 19}$
What is the order of magnitude of $7.81 \times 10^{- 9}$ ?
The order of magnitude of $7.81 \times 10^{- 9}$ is: $10^{- 8}$
True or False?
1000 is one order of magnitude larger than 100.
True.
One order of magnitude larger is ten times larger.
- $10 \times 100 = 1000$
True or False?
$10^{28}$ is two orders of magnitude larger than $5.6 \times 10^{26}$ .
False.
Two orders of magnitude larger than $5.6 \times 10^{26}$ is $10^{29}$ .
The order of magnitude of $5.6 \times 10^{26}$ is $10^{27}$ .
Two orders of magnitude larger is one hundred times larger.
- $10^{27} \times 10^{2} = 10^{29}$
Estimate the order of magnitude of the diameter of a hydrogen atom.
The order of magnitude of the diameter of a hydrogen atom is $~ 10^{- 10}$ m.
Estimate the order of magnitude of the length of a car.
The order of magnitude of the length of a car is $~ 10^{0}$ m.
Estimate the order of magnitude of the diameter of the Earth.
The order of magnitude of the diameter of the Earth is $~ 10^{7}$ m.
What is $426 019$ in scientific notation to one significant figure?
$426 019$ in scientific notation to one significant figure is $4 \times 10^{5}$ .
What is $105 026 132$ in scientific notation to two significant figures?
$105 026 132$ in scientific notation to two significant figures is $1.1 \times 10^{8}$ .
What is $0.002053$ in scientific notation to two significant figures?
$0.002053$ in scientific notation to two significant figures is $2.1 \times 10^{- 3}$ .
True or False?
All digits of an integer number are significant if the last digit is non-zero.
True.
All digits of an integer number are significant if the last digit is non-zero.
- For example, 702 has 3 significant figures
True or False?
Zeros at the end of an integer number are always significant.
False.
Zeros at the end of an integer number are never significant.
- For example, 306 000 has 3 significant figures
True or False?
Zeros in front of an integer number are never significant.
True.
Zeros in front of an integer number are never significant.
- For example, 0.025 has 2 significant figures
True or False?
Zeros at the end of a number less than one are never significant.
False.
Zeros at the end of a number less than one are always significant.
- For example, 0.02000 has 4 significant figures
True or False?
Zeros after an integer number that has a decimal point are always significant.
True.
Zeros after an integer number that has a decimal point are always significant.
- For example, 40.0 has 3 significant figures
What is dimensional analysis?
Dimensional analysis is a method used to check the homogeneity of physical equations by studying the units.
Show that the equation $p = m v$ is a homogeneous equation.
An equation is homogeneous if the SI base units are the same on both sides.
- $p = m v$
- $[kg m s^{- 1}] = [kg] \times [m s^{- 1}]$
- $[kg m s^{- 1}] = [kg m s^{- 1}]$
Show that the equation $E_{k} = \frac{p^{2}}{2 m}$ is a homogeneous equation.
An equation is homogeneous if the SI base units are the same on both sides.
- $E_{k} = \frac{p^{2}}{2 m}$
- $[kg m^{2} s^{- 2}] = \frac{[{kg}^{2} m^{2} s^{- 2}]}{[kg]}$
- $[kg m^{2} s^{- 2}] = [kg m^{2} s^{- 2}]$
Show that the equation $P = F v$ is a homogeneous equation.
An equation is homogeneous if the SI base units are the same on both sides.
- $P = F v$
- $\frac{[kg m^{2} s^{- 2}]}{[s]} = [kg m s^{- 2}] \times [m s^{- 1}]$
- $[kg m^{2} s^{- 3}] = [kg m^{2} s^{- 3}]$
Show that the equation $T = 2 π \sqrt{\frac{m}{k}}$ is a homogeneous equation.
An equation is homogeneous if the SI base units are the same on both sides.
- $T = 2 π \sqrt{\frac{m}{k}}$
- $\frac{1}{[s]} = \sqrt{\frac{[kg]}{[N m^{- 1}]}} = \sqrt{\frac{[kg]}{[kg m s^{- 2}] [m^{- 1}]}}$
- $\frac{1}{[s]} = \sqrt{\frac{1}{[s^{- 2}]}} = \frac{1}{[s]}$
Define the term resolution of a measuring instrument.
The resolution of a measuring instrument is the smallest change in the physical quantity being measured that results in a change in the reading given by the measuring instrument.
What steps need to be taken for an experiment to be valid.
For an experiment to be valid, any variable that may affect the results needs to be controlled for.
Why is it important to calibrate measuring equipment prior to taking any readings?
It is important to calibrate measuring equipment prior to taking any readings to make sure the values given by the measuring device are accurate.
What is an independent variable?
An independent variable is a variable that is changed on purpose in order to observe the effects of the change.
What is a dependent variable?
A dependent variable is a variable that changes in response to changing the independent variable. The effects of this change are predicted, observed, and measured.
What is a control variable?
A control variable is any other factor that may affect the results of the investigation and must therefore be controlled for as far as possible.
A student is measuring the terminal velocity of a ball bearing in different fluids.
State the following variables for this investigation:
- independent variable
- dependent variable
- control variables
For a student measuring the terminal velocity of a ball bearing in different fluids, the variables are as follows:
- independent variable - terminal velocity of ball bearing
- dependent variable - type of fluid
- control variables - height of free fall, diameter and mass of ball bearing