Physics: Average Speed and Velocity

Average Speed

• Average speed is calculated by dividing total distance traveled by total time taken.
• Formula: average speed = Total distance traveled / Total time taken
• Example: A car travels 100 km in 2 hours, its average speed is 50 km/h.

Average Velocity

• Average velocity is the arithmetic mean of initial and final velocity for a given period of time.
• Formula: average velocity = (initial velocity + final velocity) / 2
• Example: An object travels 16 m in 4 s and then another 16 m in 2 s, its average speed can be calculated.

Speed and Velocity

• Speed and velocity have the same units (m/s or m s-1).
• Speed only has magnitude, while velocity has both magnitude and direction.
• Velocity can be uniform or variable, and can be changed by changing speed, direction of motion, or both.

Acceleration

• Acceleration is the change in velocity of an object per unit time.
• Formula: acceleration = (change in velocity) / time taken
• Acceleration is a measure of the rate of change of velocity.

Accelerated Motion

• Accelerated motion is a type of motion where velocity changes.
• Example: A bicycle's velocity changes from 0 to 6 m/s in 30 s, and then changes from 6 m/s to 4 m/s in 5 s.

Units of Speed

• SI unit of speed is m/s or m s-1.
• Other units of speed include cm/s and km/h.

Displacement and Distance

• Displacement is the distance measured from the initial to the final position of an object.
• The magnitude of displacement can be equal to the distance travelled by an object, but not always.

Odometer and Distance Travelled

• An odometer is a device that shows the distance travelled by a vehicle.
• The difference between the final and initial readings of an odometer gives the distance travelled.

Speed and Velocity

• Speed is the rate at which an object moves, measured by the distance travelled by the object in unit time.
• The SI unit of speed is metre per second (m s–1).
• Speed can be uniform or variable.
• Velocity is the speed of an object moving in a definite direction, specifying both speed and direction.
• Velocity can be uniform or variable.

Uniform Motion

• In uniform motion, the velocity of an object remains constant with time.
• The path of an object in uniform motion is a straight line.

Non-Uniform Motion

• In non-uniform motion, velocity varies with time.
• The rate of motion of an object can be expressed in terms of average velocity.

Average Speed and Average Velocity

• Average speed is the total distance travelled divided by the total time taken.
• Average velocity is the total displacement divided by the total time taken.
• Average speed and average velocity can be different.

Example Problems

• Calculating average speed and average velocity from given data.
• Finding distance travelled and displacement from odometer readings.

Key Concepts

• Displacement is a vector quantity, while distance is a scalar quantity.
• Speed is a scalar quantity, while velocity is a vector quantity.
• Uniform motion and non-uniform motion have different characteristics.

Learn about the formulas and calculations of average speed and velocity, with examples and explanations.