Physics - Term 2 - Week 1

Kinematics is the branch of physics that describes the motion of objects. It focuses on quantities such as displacement, distance, speed, velocity, and acceleration. Displacement is a vector quantity that refers to the change in position of an object, while distance is a scalar quantity that measures the total path traveled. Speed is the rate at which an object covers distance, whereas velocity includes both speed and direction. Acceleration is the rate of change of velocity over time.

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 5 seconds, the average velocity can be calculated as displacement divided by time: 50 meters east / 5 seconds = 10 m/s east.

A cyclist starts from rest and reaches a speed of 20 m/s in 10 seconds. To find the acceleration, we use the formula: acceleration = (final velocity - initial velocity) / time. Here, acceleration = (20 m/s - 0 m/s) / 10 s = 2 m/s². Students should practice similar problems, calculating acceleration from different initial and final velocities.

Students will solve a set of problems involving kinematic equations. For example, if a car accelerates uniformly from rest to 25 m/s over a distance of 200 meters, they will need to determine the acceleration and the time taken. They should apply the equations of motion: v² = u² + 2as and v = u + at, where u is the initial velocity, v is the final velocity, a is acceleration, and s is displacement.

• Speed is a vector, velocity is a scalar.
• Speed is a scalar, velocity is a vector.
• Both are the same.
• Speed includes direction, velocity does not.

Answer: Speed is a scalar, velocity is a vector.

Speed measures how fast an object moves without regard to direction, while velocity includes both speed and direction.

Answer: Displacement is the vector quantity that represents the change in position of an object.

Displacement considers the shortest path from the initial to the final position, including direction.

• 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 shows how acceleration is the rate of change of velocity over time.

• 30 m/s
• 25 m/s
• 20 m/s
• 15 m/s

Answer: 30 m/s

Average speed is calculated as total distance divided by total time: 150 m / 5 s = 30 m/s.

Answer: Uniform acceleration means that the rate of change of velocity is constant over time.

In uniform acceleration, an object speeds up or slows down at a steady rate.

• Displacement
• Velocity
• Speed
• Acceleration

Answer: Speed

Speed is a scalar quantity as it only has magnitude and no direction.