Physics - Term 2 - Week 6

Kinematics is the branch of physics that describes the motion of objects without considering the forces that cause the motion. Key terms include displacement, which is the change in position of an object, and distance, which is the total path length traveled. Speed is a scalar quantity representing how fast an object moves, while velocity is a vector quantity that includes direction. Acceleration is the rate of change of velocity over time, indicating how quickly an object speeds up or slows down.

Consider a car that travels 100 meters east and then 50 meters west. The total distance traveled is 150 meters, but the displacement is 50 meters east. If this journey takes 10 seconds, the average velocity can be calculated as displacement divided by time, which is 50 meters east divided by 10 seconds, resulting in an average velocity of 5 meters per second east.

Students will be provided with a velocity-time graph of a moving object. They will identify key features such as the slope of the graph, which represents acceleration, and the area under the graph, which represents displacement. For example, if the graph shows a straight line with a positive slope, students will conclude that the object is accelerating uniformly.

Students will be tasked with solving a series of problems using the kinematic equations. For instance, they might be asked to find the final velocity of an object that starts from rest and accelerates at 2 m/s² over a distance of 50 meters. They will apply the equation v² = u² + 2as, where u is the initial velocity, a is acceleration, and s is displacement.

• Distance is a vector, displacement is a scalar.
• Distance is the total path length, displacement is the shortest path.
• Distance includes direction, displacement does not.
• There is no difference.

Answer: Distance is the total path length, displacement is the shortest path.

Distance measures the total length of the path traveled, while displacement measures the straight-line distance from the initial to the final position.

• Speed
• Distance
• Velocity
• Time

Answer: Velocity

Velocity is a vector quantity because it has both magnitude and direction, while speed and distance are scalar quantities.

Answer: Acceleration is the rate of change of velocity over time.

Acceleration indicates how quickly an object is speeding up or slowing down.

• It is increasing.
• It is decreasing.
• It is zero.
• It is negative.

Answer: It is zero.

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

Answer: The slope of a velocity-time graph represents acceleration.

The slope indicates how quickly the velocity of an object is changing.

• v = u + at
• s = ut + 1/2 at²
• v² = u² + 2as
• s = vt

Answer: v = u + at

This equation relates final velocity (v) to initial velocity (u), acceleration (a), and time (t).