Higher Advanced Physics SQA

Kinematic Relationships

Kinematic Relationships

Constant Speed

• Fundamental definition of speed is distance divided by time.
• For an object travelling at a constant speed - distance = speed x time.
• Use scalar terms, speed is a scalar quantity, it has magnitude but no direction.

Constant Acceleration

• Acceleration is defined as the rate of change of velocity per unit time.
• For an object moving with constant acceleration, it follows three kinematic equations:
  • final velocity = initial velocity + acceleration x time.
  • distance= initial velocity x time + 0.5 x acceleration x time squared.
  • final velocity squared = initial velocity squared + 2 x acceleration x distance.

Variable Acceleration

• Acceleration is variable when it is changing over time.
• In this case, apply calculus to find displacement or velocity.
• The derivative of displacement yields velocity, and its double derivative yields acceleration.

Circular Motion

• Circular motion is a special case where the object moves along a circular path.
• It has a constant speed but changing direction, hence it has acceleration known as centripetal acceleration.
• Key kinematic equations for circular motion:
  • Centripetal acceleration = velocity squared / radius.
  • Velocity for an object in circular motion = 2 x Pi x radius / Time of one complete revolution.

Projectiles

• Projectiles are objects launched into the air and subject to gravity.
• The motion of a projectile has both horizontal and vertical components.
• Horizontal motion has constant velocity while vertical motion has constant acceleration due to gravity.
• The maximum height, range and time of flight can be calculated using the principles of kinematics.

Motion in a Straight Line

• This refers to linear motion where an object travels along a straight path or line.
• Displacement is the total distance travelled in a specific direction which makes it a vector quantity.
• Linear motion example relates to Newton’s First law of Motion where an object continues to stay at rest or in motion until acted upon by an external force.