Mechanics and materials

    Cards (99)

    • What do scalars describe?
      Only a magnitude
    • What do vectors describe?
      Magnitude and direction
    • What are examples of scalars and vectors?
      Scalars:
      • Distance
      • Speed
      • Mass
      • Temperature

      Vectors:
      • Displacement
      • Velocity
      • Force/Weight
      • Acceleration
    • When should you use calculation to add vectors?
      When the two vectors are perpendicular
    • How do you find the resultant force of two perpendicular forces of 5 N and 12 N?
      Use Pythagoras' theorem
    • What is the resultant vector (R) when two forces of 5 N and 12 N are perpendicular?
      13 N
    • How do you find the direction of the resultant vector?
      Use trigonometry
    • What is the formula for finding the angle θ in a right triangle?
      tan θ = opposite/adjacent
    • What is the direction of the resultant force from the horizontal in the example given?
      22.6°
    • When should you use a scale drawing to add vectors?
      When vectors are at angles other than 90°
    • How do you find the magnitude and direction of a ship's displacement traveling at a bearing of 060°?
      Draw a scale diagram
    • What is the formula to resolve a vector V into its components x and y?
      x = V cos θ, y = V sin θ
    • What does it mean to resolve vectors?
      To break them into components
    • How do you find the vertical component of a velocity of 10 m/s at an angle of 30°?
      y = 10 sin 30°
    • How do you find the horizontal component of a velocity of 10 m/s at an angle of 30°?
      x = 10 cos 30°
    • What are the vertical and horizontal components of a ball fired at 10 m/s at 30°?
      8.7 m/s and 5 m/s
    • How do you find the vertical and horizontal components of weight on an inclined plane?
      Use sin and cos for angles
    • What is the condition for an object to be in equilibrium?
      The sum of all forces must be zero
    • How can you show an object is in equilibrium?
      • Add horizontal and vertical components of forces
      • Draw a scale diagram forming a closed triangle
    • What is the formula for the moment of a force about a point?
      Moment = Force × Perpendicular distance
    • What is a couple in physics?
      A pair of equal and opposite forces
    • How do you find the moment of a couple?
      Multiply one force by the distance
    • What does the principle of moments state?
      Sum of anticlockwise moments equals clockwise moments
    • How do you find the value of F using moments?
      Set clockwise moments equal to anticlockwise moments
    • What is the center of mass of an object?

      The point where mass acts
    • What is speed in physics?
      A scalar quantity describing how fast
    • What is displacement?
      Overall distance with direction
    • What is velocity?
      Rate of change of displacement
    • What is acceleration?
      Rate of change of velocity
    • What is instantaneous velocity?
      Velocity at a specific point in time
    • How is average velocity calculated?
      Final displacement divided by time
    • What is uniform acceleration?
      Constant acceleration of an object
    • What do acceleration-time graphs represent?
      Change in acceleration over time
    • What do velocity-time graphs represent?
      Change in velocity over time
    • What do displacement-time graphs represent?
      Change in displacement over time
    • What formulas can be used for uniform acceleration?
      v = u + at, s = ut + 0.5at²
    • How do you find the final velocity of a stone dropped from 50 m?
      Use = + 2as
    • How do you find the time of fall for a stone dropped?
      Use s = ut + 0.5at²
    • What is projectile motion?
      Motion with independent vertical and horizontal components
    • How do you find the maximum height of a projectile?
      Use vertical component until v = 0
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