AP Physics 1: Unit 1 Kinematics Review

Preliminary Topics

Significant Figures

• AP Physics 1 exam largely ignores significant figures.
• Use roughly 3 significant figures.

Conversions

• Conversions help with understanding physics concepts.
• Example: Convert 8,765 kg/m³ to g/cm³.
  • Multiply by 1000 g/1 kg and (1 m/100 cm)³.
  • Result: 8.77 g/cm³.

Vectors and Scalars

Definitions

• Vectors: Have magnitude and direction.
• Scalars: Have magnitude only.

Examples

• Vector Examples: Displacement, velocity, acceleration, force, momentum, torque, angular momentum.
• Scalar Examples: Time, distance, mass, speed, volume, density, work, energy, rotational inertia.

Representation

• Variables identified as vectors: arrow, subscript, boldface.
• Vector diagrams: Arrow length indicates magnitude.

Displacement

• Definition: Change in position, straight-line distance between initial and final location.
• Formula: Δx = x_final - x_initial.
• Properties:
  • Vector quantity.
  • Displacement can be zero if start and end points are the same.

Speed and Velocity

Speed

• Definition: Distance traveled over time duration.
• Formula: Speed = Distance/Time.
• Scalar quantity.

Velocity

• Definition: Displacement over change in time.
• Formula: Velocity = Displacement/Time.
• Vector quantity.

Instantaneous vs. Average

• Instantaneous Velocity: At a specific time.
• Instantaneous Acceleration: At a specific time.

Acceleration

• Definition: Change in velocity over change in time.
• Formula: Acceleration = ΔVelocity/ΔTime.
• Vector quantity.
• Units: m/s².

Uniformly Accelerated Motion (UAM) Equations

• Used when acceleration is constant.
• UAM Variables: Acceleration, velocity final, velocity initial, displacement, change in time.
• UAM Equations: Provided on equation sheet. Displacement = 1/2(Velocity final + Velocity initial) x time.
• Analysis: Knowing 3 variables allows calculation of the other 2.
• Instantaneous Velocities: Used in UAM equations.

Free Fall

• Force: Only gravity acts on the object.
• Acceleration: 9.81 m/s² downward or use 10 m/s² for exams.
• Velocity at Top: Zero in y-direction.
• UAM Equations: Applicable due to constant acceleration.

Motion Graphs

Position vs. Time

• Slope: Represents velocity.

Velocity vs. Time

• Slope: Represents acceleration.
• Area under Curve: Represents change in position.

Acceleration vs. Time

• Area under Curve: Represents change in velocity.

Graph Analysis

• Positive/Negative Areas: Above axis = positive, below axis = negative.
• Consistency: Cannot describe one object with all three graphs.

Projectile Motion

• Resolution of Vectors: Into x and y components using trigonometry.
• X-Direction: Constant velocity due to zero acceleration.
• Y-Direction: Free fall under gravity.
• Calculations: Use time as a common variable.

Relative Motion

• Concept: Motion description varies with observer's frame of reference.
• Vector Addition: Use to solve problems involving velocities relative to different frames.

Conclusion

• Summary of Unit 1 including concepts of kinematics.
• Mention of additional resources like the Ultimate Review Packet for further study.