Physics - Term 1 - Week 10

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; distance, the total path length traveled; speed, the rate at which distance is covered; velocity, which includes direction; and acceleration, the rate of change of velocity. Understanding these concepts is essential for analyzing motion.

Consider a car that travels 100 meters east and then 50 meters west. To find the displacement, we subtract the distance traveled in the opposite direction from the distance traveled in the initial direction. Thus, the displacement is 100 m - 50 m = 50 m east. This example illustrates how displacement differs from distance, as it considers direction.

A cyclist travels 150 meters in 10 seconds. To find the average velocity, we use the formula: velocity = displacement / time. Here, the displacement is 150 m, and the time is 10 s. Therefore, the average velocity is 150 m / 10 s = 15 m/s. Students should practice calculating average velocity with different distances and times to reinforce their understanding.

Students will solve problems involving acceleration. For example, if a car increases its velocity from 20 m/s to 50 m/s in 5 seconds, what is the acceleration? Using the formula: acceleration = (final velocity - initial velocity) / time, students will find that acceleration = (50 m/s - 20 m/s) / 5 s = 6 m/s². Additional problems will be provided for practice.

• The total distance traveled by an object.
• The shortest distance from the initial to the final position.
• The speed of an object in a specific direction.
• The rate of change of velocity.

Answer: The shortest distance from the initial to the final position.

Displacement is defined as the shortest straight-line distance from the starting point to the endpoint, including direction.

• 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: 8 m/s

Average speed is calculated as total distance divided by total time: 400 m / 50 s = 8 m/s.

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

Answer: It is zero.

An object moving with constant velocity has no change in speed or direction, resulting in zero acceleration.

Answer: a = (v_f - v_i) / t

Acceleration is calculated using the formula where 'a' is acceleration, 'v_f' is final velocity, 'v_i' is initial velocity, and 't' is time.

• 3 m/s²
• 6 m/s²
• 10 m/s²
• 15 m/s²

Answer: 3 m/s²

Using the formula a = (v_f - v_i) / t, we have a = (30 m/s - 0 m/s) / 10 s = 3 m/s².

• Motion with varying speed.