Physics - Term 2 - Week 3

Kinematics is the branch of physics that describes the motion of objects without considering the forces that cause the motion. In one-dimensional motion, we focus on how an object moves along a straight line. Displacement refers to the change in position of an object and is a vector quantity, meaning it has both magnitude and direction. Distance, on the other hand, is a scalar quantity that measures the total path length traveled. Velocity is defined as the rate of change of displacement with respect to time, while acceleration is the rate of change of velocity. Understanding these concepts is crucial for analyzing motion.

Consider a car that travels 100 meters east and then 50 meters west. To find the displacement, we calculate the net change in position: Displacement = 100 m (east) - 50 m (west) = 50 m (east). If this journey takes 10 seconds, the average velocity can be calculated as: Velocity = Displacement / Time = 50 m / 10 s = 5 m/s (east). This example illustrates how to determine both displacement and velocity from a given motion scenario.

A cyclist accelerates from rest to a speed of 20 m/s in 5 seconds. To find the acceleration, we use the formula: Acceleration = (Final Velocity - Initial Velocity) / Time. Here, Initial Velocity = 0 m/s, Final Velocity = 20 m/s, and Time = 5 s. Thus, Acceleration = (20 m/s - 0 m/s) / 5 s = 4 m/s². Students should practice similar problems, calculating acceleration for different scenarios, ensuring they understand the relationship between velocity, time, and acceleration.

Students will complete a worksheet with various problems involving displacement, velocity, and acceleration. For example, one problem might state: 'A runner completes a 400 m lap in 50 seconds. Calculate the average velocity.' Students should apply the formula for average velocity and show their work. This independent practice will reinforce the concepts learned in class and allow students to apply their knowledge to new situations.

• The total distance traveled by an object.
• The change in position of an object.
• The speed of an object in a given direction.
• The rate of change of velocity.

Answer: The change in position of an object.

Displacement measures how far out of place an object is; it is the object's overall change in position.

• Velocity
• Displacement
• Distance
• Acceleration

Answer: Distance

Distance is a scalar quantity as it only has magnitude and no direction, unlike displacement which is a vector.

Answer: 5 m/s east

Average velocity is calculated as displacement divided by time: 150 m / 30 s = 5 m/s east.

• It is increasing.
• It is decreasing.
• It is zero.
• It is constant.

Answer: It is zero.

Constant velocity means there is no change in speed or direction, hence acceleration is zero.

Answer: Acceleration = (Final Velocity - Initial Velocity) / Time

This formula expresses how acceleration is the change in velocity over the time taken for that change.

• 5 m/s²
• 10 m/s²
• 2.5 m/s²
• 4 m/s²

Answer: 5 m/s²

Using the formula for acceleration: (30 m/s - 10 m/s) / 4 s = 5 m/s².

• Acceleration changes over time.
• Velocity changes at a constant rate.