Unit 1 - Kinematics

• What is a scalar quantity?

  A scalar is a quantity that has magnitude and no direction.
• What is a vector quantity?

  A vector is a quantity that has magnitude and has direction.
• What is the SI unit of velocity?

  The SI unit of velocity is m/s.

  
• What is the SI unit of speed?

  The SI unit of speed is m/s.

  
• How does acceleration relate to direction?

  Acceleration can be either accelerating, pointing in the same direction, or decelerating, pointing in the opposite direction.
• What are the differences between vectors and scalars?

  • Vectors:
  • Direction dependent
  • Notated with an arrow above
  • Examples: Displacement, Velocity, Acceleration, Force
  • Scalars:
  • Magnitude only
  • Independent of direction
  • Examples: Distance, Speed, Volume, Energy, Density, Time Interval, Mass

  
• What is the net force symbolized as?

  The net force is symbolized as \( F_{net} \) or \( \Sigma F \).
• If a child has a weight of 63 N and pulls up with 14.5 N while standing on two scales, what must scale 2 register if scale 1 shows 21.5 N?

  Scale 2 must register 27 N.
• What is the difference between distance and displacement in Cindy's 5k run?

  The displacement and the distance are different since she is not running in a straight line.
• What is the average speed of Cindy if she runs at 4.3 m/s for a 5k race?

  Her average speed is 4.3 m/s.
• What does it mean if someone is moving at a constant speed of 10 m/s?

  It means that the person moves 10 m every second.
• How fast was Jim riding his bicycle before he got a flat tire if he took 8 minutes to get home after riding 0.5 miles and walking the rest at 2.1 m/s?

  Jim was riding at 8.29 m/s.
• How do you rank cows based on their speed in the cow racing competition?

  Rank them based on the steepness of the slope; the steeper the slope, the greater the position change (displacement) in a given time.
• What does a steep slope on a position vs. time graph indicate about an object's motion?

  A steep slope indicates that the object is traveling at a greater velocity/speed.

  
• What does the area under the curve represent in a velocity vs. time graph?

  The area under the curve equals the displacement.

  
• What are the key kinematic formulas for uniform accelerated motion?

  1. \( \Delta v = v - v_0 \)
  2. Displacement = area under the line
  3. \( \Delta x = x - x_0 \)
• What is the acceleration due to gravity?

  The acceleration due to gravity is \( -9.8 \, \text{m/s}^2 \).
• What does it mean if a horse gallops with a constant acceleration of 3 m/s²?

  It means the horse’s velocity increases by 3 m/s every second.
• If Cindy accelerates at 2.4 m/s² for 5 seconds, how fast are they moving?

  They are moving at 32 m/s.
• If a speeder maintains a constant velocity of 40 mi/hr (17.9 m/s), what happens when the police car accelerates at 4.5 m/s²?

  The police car will eventually catch up to the speeder if it maintains its acceleration.
• What is the relationship between velocity and acceleration in terms of direction?

  • If velocity and acceleration point in the same direction, speed increases (positive acceleration).
  • If velocity and acceleration point in opposite directions, speed decreases (negative acceleration).
• What are the characteristics of a position vs. time graph?

  • Slope/gradient equals velocity.
  • The y-intercept equals initial displacement.
  • A straight line represents constant velocity.
  • A curved line represents accelerated motion.
  • Positive slope indicates motion in the positive direction.
  • Negative slope indicates motion in the negative direction.
  • Zero slope indicates rest.

  
• What are the characteristics of a velocity vs. time graph?

  • Slope equals acceleration.
  • The y-intercept equals initial velocity.
  • A straight line represents uniform acceleration.
  • A curved line represents non-uniform accelerated motion.
  • Positive slope indicates an increase in velocity in the positive direction.
  • Negative slope indicates an increase in velocity in the negative direction.
  • Zero slope indicates constant velocity.
  • Area under the curve equals displacement.
• What is the formula for calculating displacement in a velocity vs. time graph?

  Displacement is equal to the area between the line and the horizontal axis.

  
• What does it mean for a car's velocity to decrease as shown in a velocity vs. time graph?

  It means that the car's acceleration changes from positive to negative.

  
• How can you determine if a car's speed is increasing or decreasing from a velocity vs. time graph?

  If the slope is positive, the speed is increasing; if the slope is negative, the speed is decreasing.
• What does it mean when the average velocity is the same between two time intervals?

  It means that the displacement during those intervals is equal.

  
• What is the formula for calculating average velocity?

  Average velocity is calculated as \( \text{Average Velocity} = \frac{\Delta x}{\Delta t} \).

  
• What does it mean if an object is accelerating?

  It means that the object's velocity is changing over time.

  
• How can you tell if an object is experiencing uniform acceleration from a graph?

  If the graph is a straight line, it indicates uniform acceleration.

  
• What does a negative acceleration indicate about an object's motion?

  Negative acceleration indicates that the object is slowing down.

  
• What is the formula for calculating acceleration?

  Acceleration is calculated as \( a = \frac{\Delta v}{\Delta t} \).

  
• How does acceleration relate to velocity in terms of direction?

  Acceleration can either increase or decrease velocity depending on whether it is in the same or opposite direction.
• What can be inferred if a velocity vs. time graph shows a horizontal line?

  A horizontal line indicates that the object is moving at a constant velocity.

  
• What does it mean if the area under the curve in a velocity vs. time graph is zero?

  It means that there is no displacement during that time interval.

  
• What is the formula for calculating displacement from a velocity vs. time graph?

  Displacement is equal to the area under the curve of the velocity vs. time graph.

  
• What does it mean if a car's velocity is increasing uniformly with time?

  It means that the car is experiencing a constant positive acceleration.

  
• How can you determine the acceleration of an object from a velocity vs. time graph?

  Acceleration can be determined by calculating the slope of the line on the graph.
• What does it indicate if the velocity vs. time graph has a negative slope?

  A negative slope indicates that the object's velocity is decreasing over time.
• What is the relationship between acceleration and velocity in terms of direction?

  If acceleration and velocity point in the same direction, speed increases; if they point in opposite directions, speed decreases.