Physics - Term 2 - Week 5

Kinematics is the branch of physics that deals with the motion of objects without considering the forces that cause the motion. 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 is speed with a direction. Acceleration is the rate of change of velocity over time. Understanding these concepts is crucial for analyzing motion.

Consider a car that travels 100 meters north and then 40 meters south. To find the displacement, we subtract the distance traveled south from the distance traveled north. Thus, the displacement is 100 m - 40 m = 60 m north. This example illustrates how displacement can differ from the total distance traveled.

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 will now calculate the average velocity for a runner who covers 200 meters in 25 seconds.

Students will solve the following problems independently: 1. A car accelerates from rest to 20 m/s in 5 seconds. Calculate the acceleration. 2. A ball is thrown upwards with an initial velocity of 30 m/s. How high does it go before it starts to fall back down? Students should apply the kinematic equations to find the solutions.

• Speed is a vector; velocity is a scalar.
• Speed is a scalar; velocity is a vector.
• Both are the same.
• Velocity is always greater than speed.

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

Speed does not have a 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 between the initial and final positions.

• 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 zero acceleration.

Answer: Acceleration = (final velocity - initial velocity) / time.

This formula shows how acceleration is the change in velocity over a specific time interval.

• 60 km/h
• 120 km/h
• 30 km/h
• 90 km/h

Answer: 60 km/h

Average speed is calculated by dividing the distance traveled by the time taken.

Answer: A motion graph visually represents the relationship between distance and time or velocity and time.

These graphs help in understanding how an object's position or speed changes over time.

• Distance
• Speed
• Displacement
• Time

Answer: Displacement

Displacement has both magnitude and direction, making it a vector quantity.