3.1 Quantities and Units in Mechanics

• Scalar quantities require direction to be fully described.

  False
• Vector quantities require direction to be fully described.


  True
• Scalar quantities require direction to be fully described.

  False
• What is the SI unit for force?

  Newton
• The International System of Units (SI) ensures consistency and accuracy in scientific calculations
• What is the SI unit for time?

  second
• The International System of Units (SI) is used only in physics.

  False
• What is the magnitude of mass in scalar quantities?

  Quantity of matter
• Scalar quantities have only magnitude
• Vector quantities have both magnitude and direction
• What is the SI unit for time?

  Second
• What is the SI unit for velocity?

  Meters per second
• Vector quantities require direction to be fully described.

  True
• What is the SI unit for length?

  meter
• How many meters are in 3.5 kilometers?

  3500
• What does time measure in scalar quantities?

  Duration of an event
• Velocity is an example of a vector quantity.


  True
• Momentum is defined as mass times velocity and has the unit kg m/s.
• Match the scalar quantity with its unit of measurement:

  Mass ↔️ Kilogram

  Time ↔️ Second

  Distance ↔️ Meter

  Speed ↔️ Meters per second

  Energy ↔️ Joule
• Match the vector quantity with its unit of measurement:

  Velocity ↔️ Meters per second

  Displacement ↔️ Meter

  Force ↔️ Newton

  Acceleration ↔️ Meters per second squared

  Momentum ↔️ Kilogram meters per second
• What is the SI unit for distance?

  Meter
• What is the SI unit for displacement?

  Meter
• Match the basic SI unit with its quantity:

  Length ↔️ Meter

  Mass ↔️ Kilogram

  Time ↔️ Second
• What is the SI unit for mass?

  kilogram
• The SI unit for velocity is meters per second
• Scalar quantities have both magnitude and direction.

  False
• Match the scalar quantity with its magnitude and units:

  Mass ↔️ Quantity of matter (kg)

  Time ↔️ Duration of an event (s)

  Distance ↔️ Length between two points (m)

  Speed ↔️ Rate of motion (m/s)
• Displacement measures the change in position of an object.
• Match the vector quantity with its magnitude, direction, and units:

  Velocity ↔️ Speed, Direction of motion (m/s)

  Force ↔️ Strength of interaction, Direction of action (N)

  Momentum ↔️ Mass times velocity, Direction of velocity (kg m/s)

  Displacement ↔️ Distance, Change in position (m)
• One kilometer is equal to 1000 meters.


  True
• Match the original unit with its conversion factor to meters:

  Kilometer (km) ↔️ 1 km = 1000 m

  Meter (m) ↔️ 1 m = 1 m

  Centimeter (cm) ↔️ 1 cm = 0.01 m

  Millimeter (mm) ↔️ 1 mm = 0.001 m
• What are the dimensions of velocity in terms of basic dimensions?

  LT⁻¹
• The dimensions of physical quantities describe the types of quantities involved without numerical values
• What is the dimension of force in mechanics?

  ML/T²
• Dimensional analysis can identify errors in formulas by ensuring both sides have matching dimensions.

  True
• What is the unit of mass?

  kilograms (kg)
• Scalar quantities have only magnitude and no direction.
• What are the basic SI units for mechanics?

  meter, kilogram, second
• What does the International System of Units (SI) provide for science and engineering?

  Standardized system for measuring
• Why are unit conversions essential in mechanics?

  Ensure consistency and accuracy