our dynamic universe

• how do we add vectors?

  we can use a scale drawing or trig
• when can we add vectors?

  we can add 2 vectors of the same type.

  we need to account for both magnitude and direction.
• what are rectangular components?

  any vector can be broken down into the sum of other vectors.

  we typically resolve a vector into the sum of two vectors at 90* to each other, the rectangular components.
• what do we do when calculating rectangular components?

  first we calculate,

  • initial vertical velocity
  • horizontal velocity

  we do this by using SOH CAH TOA
• what are the 2 rules of linear motion (equations)?

  1. the motion is along a straight line
  2. the acceleration is constant.
• what are the 3 equations of linear motion?

  • V=u+at
  • S=ut+1/2atsquared
  • Vsquared=usquared+2as
• what do the equations of motion predict?

  they predict the motion of any object which obeys the 2 rules.
• what are the graphs of motion used for?

  Graphs of displacement, velocity or acceleration against time are useful tools for examining motion/movement.
• What does the gradient of an s-t graph represent?

  Velocity
• What does the gradient of a v-t graph represent?

  Acceleration
• What does the area under a v-t graph represent?

  Displacement
• What are the characteristics of time graphs in higher level graphs?

  • Only dealing with time graphs
  • Represent motion over time
• What is the unit of acceleration?

  ms⁻²
• What is the starting speed of an object that is dropped?

  Zero
• What is the starting speed of a thrown object?

  Non-zero
• What happens to an object in motion eventually?

  It ceases to move
• What is the acceleration due to gravity denoted as?


  g
• What does the Dropped Ball graph indicate about the motion of the ball?

  • Dotted line indicates hitting the ground
  • Changes direction upon impact
  • Initial velocity is zero
  • Gradient equals g (gravity)
• What does the Thrown Ball graph indicate about the motion of the ball?

  • Non-zero initial starting point
  • Peaks get smaller with each bounce
  • Energy loss as kinetic energy converts to heat and sound
• What is a projectile?

  Any object moving such that the only force on it is weight due to gravity.
• What type of velocity does a projectile have?

  Constant horizontal velocity
• What is the vertical acceleration of a projectile on Earth?

  $9.8 \text{ ms}^{-2}$ down
• What path do all projectiles follow?

  A projectile path
• How can we analyze projectile motion effectively?

  • Split motion into horizontal and vertical components
  • Treat each component separately
• When does maximum height occur in a projectile path?

  Halfway through the projectile path
• What is the vertical velocity at maximum height?

  Vertical velocity = $0 \text{ ms}^{-1}$
• How do we break down launch velocity in projectile motion?

  Into rectangular components
• What are forces measured in?

  Newtons
• How do forces in the same direction behave?

  They add together
• What happens to forces in opposite directions?

  They cancel out
• What does Newton's 1st Law state?

  if the forces on an object are balanced (the same in opposite directions) it has a constant velocity.
• What is the formula for Newton's 2nd Law?

  $F =$$ma$
• What does Newton's 3rd Law state?

  For every action, there is an equal reaction
• How can we find rectangular components of forces?

  • Use trigonometric functions
  • Resolve forces into horizontal and vertical components
• What are internal forces in a system of connected objects?

  In a situation where multiple connected objects (a system) is being moved. we may be asked about internal forces these are the Forces applied by components on each other
• What is tension in a connection between two objects?

  The pulling force towards the middle
• How do we solve questions involving internal forces?

  Using Newton's laws
• What happens to the reading on a scale in an elevator?

  1. Constant velocity: Reading = weight = $mg$
  2. Accelerating upwards: Reading = $mg +$$ma$
  3. Accelerating downwards: Reading = $mg - ma$
  4. Freefall: Reading = 0
• What does the scale read when the elevator is stationary?

  Weight = $mg$
• What happens to the scale reading when the elevator accelerates upwards?

  The reading increases