Physics - Term 3 - Week 1

Kinematics is the branch of physics that describes the motion of objects without considering the forces that cause the motion. The three fundamental quantities in kinematics are displacement, velocity, and acceleration. Displacement is the change in position of an object and is a vector quantity, meaning it has both magnitude and direction. Velocity, also a vector, is defined as the rate of change of displacement over time. Acceleration measures how quickly velocity changes and is also a vector quantity. The relationships between these quantities can be expressed through equations of motion.

A car travels 100 meters to the east and then 50 meters to the west. To find the total displacement, we consider the direction. The displacement is 100 m (east) - 50 m (west) = 50 m (east). This example illustrates how to calculate displacement by considering the direction of motion.

Let's calculate the average velocity of a runner who completes a 400-meter lap in 50 seconds. The average velocity is given by the formula: velocity = displacement/time. Here, the displacement is 400 meters, and the time is 50 seconds. Therefore, the average velocity is 400 m / 50 s = 8 m/s. Students should practice calculating average velocity using different distances and times provided by the teacher.

Students will solve a series of problems involving acceleration. For example, if a car increases its velocity from 20 m/s to 60 m/s in 5 seconds, what is its acceleration? Students should use the formula: acceleration = (final velocity - initial velocity) / time. They will calculate the acceleration and then apply this to various scenarios, such as objects in free fall or vehicles accelerating on a road.

• Meters
• Seconds
• Kilograms
• Newtons

Answer: Meters

Displacement is measured in meters, which is the standard unit of length in the International System of Units (SI).

• Speed
• Distance
• Velocity
• Time

Answer: Velocity

Velocity is a vector quantity because it has both magnitude and direction, unlike speed which only has magnitude.

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

Acceleration indicates how quickly an object's velocity changes, and it can be positive (speeding up) or negative (slowing down).

• It is increasing
• It is decreasing
• It is zero
• It is variable

Answer: It is zero

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

Answer: Average velocity = Displacement / Time

This formula shows how average velocity is derived from the total displacement of an object divided by the time taken.

• 15 km/h
• 30 km/h
• 60 km/h
• 20 km/h

Answer: 15 km/h

Average speed is calculated as total distance divided by total time. Here, 30 km / 2 hours = 15 km/h.

• d = vt
• d = vi + 1/2 at^2
• d = vi + vt
• d = v^2 - u^2

Answer: d = vi + 1/2 at^2