Physics - Term 2 - Week 10

Kinematics is the branch of physics that describes the motion of objects. It focuses on how objects move rather than 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 of change of distance; velocity, the rate of change of displacement; and acceleration, 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 take the final position minus the initial position. The displacement is 100 m - 50 m = 50 m east. This example illustrates how displacement differs from distance, which would simply be 150 meters in this case.

A cyclist travels 200 meters in 10 seconds. To find the average velocity, we use the formula: velocity = displacement/time. Here, the displacement is 200 meters, and the time is 10 seconds. Thus, the average velocity is 200 m / 10 s = 20 m/s. Students should practice calculating average velocity with different distances and times to reinforce their understanding.

Students will solve problems involving acceleration. For instance, if a car starts from rest and reaches a speed of 30 m/s in 5 seconds, what is its acceleration? Using the formula: acceleration = (final velocity - initial velocity) / time, students will find the acceleration to be (30 m/s - 0 m/s) / 5 s = 6 m/s². Students should complete a worksheet with similar problems to solidify their understanding.

• Total distance traveled
• The shortest distance from the initial to the final position
• The speed of an object
• 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, taking direction into account.

• Speed
• Distance
• Velocity
• Time

Answer: Velocity

Velocity is a vector quantity as 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. Here, 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, meaning its acceleration is zero.

Answer: a = (v_f - v_i) / t

Acceleration is calculated using the change in velocity (final velocity minus initial velocity) divided by the time taken.

• 3 m/s²
• 5 m/s²
• 2 m/s²
• 4 m/s²

Answer: 3 m/s²

Using the formula a = (v_f - v_i) / t, we have (50 m/s - 20 m/s) / 10 s = 3 m/s².

• m/s
• km/h
• m²/s